Hi. I'm very new to the designing scene and has created some sites but have some trouble with the checkbox group I have created in the form.

I used a Simple Contact form solution to get started with the code and edited it to what I needed.

I recieve the mails sent by the form but when more that 1 choice is sellected in the contact form I'm not recieving all the data sellected, onlt the last selection that was made.

Here is the code:
HTML Form:
<form action="html_form_send_1.php" method="post" enctype="multipart/form-data" name="htmlform">
<table width="960px">

<td width="330">
</tr>
<tr>
<td valign="top""><label for="name">Business Name *</label></td>
<td width="618" valign="738"><input type="text" name="name" maxlength="50" size="30"></td>
</tr>
<tr>
<td valign="top"><label for="categories">Business Categories *</label></td>
<td valign="top">
<label>
<input type="checkbox" name="categories" value="Accommodation" id="categories_0">
Accommodation</label>

<label>
<input type="checkbox" name="categories" value="Acounting" id="categories_1">
Accounting</label>

<label>
<input type="checkbox" name="categories" value="Arts & Crafts" id="categories_2">
Arts & Crafts</label>

<label>
<input type="checkbox" name="categories" value="Attorneys" id="categories_3">
Attorneys</label>
<br/>
<label>
<input type="checkbox" name="categories" value="Auctions" id="categories_4">
Auctions</label>

<label>
<input type="checkbox" name="categories" value="Automotive" id="categories_5">
Automotive</label>

<label>
<input type="checkbox" name="categories" value="Banking" id="categories_6">
Banking</label>

<label>
<input type="checkbox" name="categories" value="Carpenting" id="categories_7">
Carpenting</label>

<label>
<input type="checkbox" name="categories" value="Catering" id="categories_8">
Catering</label>
<br/>
<label>
<input type="checkbox" name="categories" value="Clubs" id="categories_9">
Clubs</label>

<label>
<input type="checkbox" name="categories" value="Construction" id="categories_10">
Construction</label>

<label>
<input type="checkbox" name="categories" value="Draughting" id="categories_11">
Draughting</label>

<label>
<input type="checkbox" name="categories" value="Education" id="categories_12">
Education</label>

<label>
<input type="checkbox" name="categories" value="Electrical" id="categories_13">
Electrical</label>
<br/>
<label>
<input type="checkbox" name="categories" value="Engineering" id="categories_14">
Engineering</label>

<label>
<input type="checkbox" name="categories" value="Entertainment" id="categories_15">
Entertainment</label>

<label>
<input type="checkbox" name="categories" value="Farming Services" id="categories_16">
Farming Services</label>

<label>
<input type="checkbox" name="categories" value="Food & Drink" id="categories_17">
Food & Drink</label>
<br/>
<label>
<input type="checkbox" name="categories" value="Funeral Services" id="categories_18">
Funeral Services</label>

<label>
<input type="checkbox" name="categories" value="Health & Beauty" id="categories_19">
Health & Beauty</label>

<label>
<input type="checkbox" name="categories" value="Hobbies" id="categories_20">
Hobbies</label>

<label>
<input type="checkbox" name="categories" value="House & Home" id="categories_21">
House & Home</label>
<br/>
<label>
<input type="checkbox" name="categories" value="Internet Services" id="categories_22">
Internet Services</label>

<label>
<input type="checkbox" name="categories" value="IT Solutions" id="categories_23">
IT Solutions</label>

<label>
<input type="checkbox" name="categories" value="Jewellers" id="categories_24">
Jewellers</label>

<label>
<input type="checkbox" name="categories" value="Mechinary" id="categories_25">
Mechinary</label>
<br/>
<label>
<input type="checkbox" name="categories" value="Medical Services" id="categories_26">
Medical Services</label>

<label>
<input type="checkbox" name="categories" value="Photography" id="categories_27">
Photography</label>

<label>
<input type="checkbox" name="categories" value="Plumbing" id="categories_28">
Plumbing</label>

<label>
<input type="checkbox" name="categories" value="Property" id="categories_29">
Property</label>
<br/>
<label>
<input type="checkbox" name="categories" value="Restorants" id="categories_30">
Restorants</label>

<label>
<input type="checkbox" name="categories" value="Retail Stores" id="categories_31">
Retail Stores</label>

<label>
<input type="checkbox" name="categories" value="Safety" id="categories_32">
Safety</label>

<label>
<input type="checkbox" name="categories" value="Scrap Yards" id="categories_33">
Scrap Yards</label>

<label>
<input type="checkbox" name="categories" value="Sports" id="categories_34">
Sports</label>
<br/>
<label>
<input type="checkbox" name="categories" value="Transport" id="categories_35">
Transport</label>

</td>

</tr>
<tr>
<td valign="top"><label for="discription">Business Discription * </label></td>
<td valign="top"><textarea name="discription" maxlength="1000" cols="30" rows="6"></textarea>1000 Characters MAX</td>
</tr>
<tr>
<td valign="top"><label for="address">Business Address * </label></td>
<td valign="top"><textarea name="address" maxlength="1000" cols="30" rows="6"></textarea>1000 Characters MAX</td>
</tr>
<tr>
<td valign="top"><label for="town">Town *</label></td>
<td valign="top"><select name="town">
<option value="<Select Town Here>" selected><Select Town Here></option>
<option value="Bethal">Bethal</option>
<option value="Secunda">Secunda</option>
<option value="Standerton">Standerton</option>
</select>
If town is not available, <a href="links.html">CLICK HERE</a> and fill out the form...</td>
</tr>
<tr>
<td valign="top"><label for="telephone">Telephone Number</label></td>
<td valign="top"><input type="text" name="telephone" maxlength="30" size="30"></td>
</tr>
<tr>
<td valign="top"><label for="cell">Cell Phone Number</label></td>
<td valign="top"><input type="text" name="cell" maxlength="30" size="30"></td>
</tr>
<tr>
<td valign="top"><label for="fax">Fax Number</label></td>
<td valign="top"><input type="text" name="fax" maxlength="30" size="30"></td>
</tr>
<tr>
<td valign="top"><label for="email">Email Address *</label></td>
<td valign="top"><input type="text" name="email" maxlength="80" size="30"></td>
</tr>
<tr>
<td valign="top"><label for="comments">Comments * </label></td>
<td valign="top"><textarea name="comments" maxlength="1000" cols="30" rows="6"></textarea>1000 Characters MAX</td>
</tr>
<tr>
<td colspan="2" style="text-align:center">By submitting this form you agree to our <a href="terms.html">Terms and Conditions</a>. Make sure you understand them.</td>
</tr>
<tr>
<td colspan="2" style="text-align:center"><input type="submit" name="Submit" id="Submit" value="Submit"></td>
</tr>
</table>
</form>

PHP Mailer Code:
<?php
if(isset($_POST['email'])) {

// CHANGE THE TWO LINES BELOW
$email_to = "banners@rfwebbanners.co.za";

$email_subject = "Banner Registration";


function died($error) {
// your error code can go here
echo "We're sorry, but there's errors found with the form you submitted.<br /><br />";
echo $error."<br /><br />";
echo "Please go back and fix these errors.<br /><br />";
die();
}

// validation expected data exists
if(!isset($_POST['name']) ||
!isset($_POST['categories']) ||
!isset($_POST['discription']) ||
!isset($_POST['address']) ||
!isset($_POST['town']) ||
!isset($_POST['email']) ||
!isset($_POST['telephone']) ||
!isset($_POST['cell']) ||
!isset($_POST['fax']) ||
!isset($_POST['comments'])) {
died('We are sorry, but there appears to be a problem with the form you submitted.');
}

$name = $_POST['name']; // required
$categories = $_POST['categories']; // required
$discription = $_POST['discription']; // required
$address = $_POST['address']; // required
$town = $_POST['town']; // required
$email_from = $_POST['email']; // required
$telephone = $_POST['telephone']; // not required
$cell = $_POST['cell']; // required
$fax = $_POST['fax']; // required
$comments = $_POST['comments']; // required

$error_message = "";
$email_exp = '/^[A-Za-z0-9._%-]+@[A-Za-z0-9.-]+\.[A-Za-z]{2,4}$/';
if(!preg_match($email_exp,$email_from)) {
$error_message .= 'The Email Address you entered does not appear to be valid.<br />';
}
$string_exp = "/^[A-Za-z .'-]+$/";
if(strlen($name) < 2) {
$error_message .= 'The Business Name you entered does not appear to be valid.<br />';
}
if(strlen($comments) < 2) {
$error_message .= 'The Comments you entered do not appear to be valid.<br />';
}
if(strlen($error_message) > 0) {
died($error_message);
}
$email_message = "Form details below.\n\n";

function clean_string($string) {
$bad = array("content-type","bcc:","to:","cc:","href");
return str_replace($bad,"",$string);
}

$email_message .= "Business Name: ".clean_string($name)."\n";
$email_message .= "Business Categories: ".clean_string($categories)."\n";
$email_message .= "Business Discription: ".clean_string($discription)."\n";
$email_message .= "Business Address: ".clean_string($address)."\n";
$email_message .= "Town: ".clean_string($town)."\n";
$email_message .= "Email: ".clean_string($email_from)."\n";
$email_message .= "Telephone: ".clean_string($telephone)."\n";
$email_message .= "Cell Number: ".clean_string($cell)."\n";
$email_message .= "Fax Number: ".clean_string($fax)."\n";
$email_message .= "Comments: ".clean_string($comments)."\n";


// create email headers
$headers = 'From: '.$email_from."\r\n".
'Reply-To: '.$email_from."\r\n" .
'X-Mailer: PHP/' . phpversion();
@mail($email_to, $email_subject, $email_message, $headers);
?>
<?php
header("refresh: 6; url= register.html"); // you can change seconds
20
?>

What should I do to fix the problem?