$to = "ben@compatibility.co.uk";
$subject = "Web Sales Enquiry";
$headers = "Content-Type: text/html; charset=iso-8859-1"; // Mime type
mail($to, $subject, $EnquiryMail, $headers) or print "Could not send mail";
That lot above will set the email to html mode, then whatever is contained in $EnquiryMail will be read as html, and you could make thet variable using somthing like this...
$EnquiryMail = "";
$EnquiryMail .= "<HEAD>\n";
$EnquiryMail .= "<style type=\"text/css\">\n";
$EnquiryMail .= "TD.pagetext { font-family: tahoma; font-size: 8pt; color: #000000; }\n";
$EnquiryMail .= "TD.pagetext2 { font-family: tahoma; font-size: 8pt; color: #313073; font-weight: bold}\n";
$EnquiryMail .= "SPAN.pagetext { font-family: tahoma; font-size: 8pt; color: #000000; }\n";
$EnquiryMail .= "SPAN.pagetext2 { font-family: tahoma; font-size: 8pt; color: #313073; font-weight: bold}\n";
$EnquiryMail .= "a:hover {font-family: tahoma; font-size: 8pt; color: #313073; text-decoration: underline;; } \n";
$EnquiryMail .= "a { font-family: tahoma; font-size: 8pt; color: #313073; text-decoration: none ; padding: 2px}\n";
$EnquiryMail .= "</style>\n";
$EnquiryMail .= "</HEAD>\n";
$EnquiryMail .= "<BODY bgcolor=\"white\">\n";
when you want a new line in the variable just use the standard \n. and obvoisly use a <BR> is you need a new line in the html, hope this helps