Not sure if this is what you're looking for.
<?
if(!isset($send)) { ?>
YOUR HTML FORM HERE
<INPUT TYPE=hidden NAME=send VALUE=yes> //make sure you put in this hidden field
<?
} else {
# Email Variables
$to="someone@mail.com";
$from="$first_name".' '."$last_name <$email>";
$subject="Subject Here";
$body="Body of Message reads::
Name: $first_name $last_name
Address: $address
City: $city
State: $state
Zip: $zip
Country: $country
Phone: $phone
Email: $email
Comments: $comments
";
# Send the mail
mail($to,$subject,$body,"From: $from");
?>
<!-- Mail Sent Message -->
<P>
<div align="center"><font face="veranda" size="4" color="#000000"> Thanks for requesting info!<br>
We'll be sending out your requested information shortly.</font> </div>
<? } ?>