Ask us to install this PHP Form Mailer for you if you host a site on our Linux servers.
You only need to change the following 2 variables, in the contact.php page:
$valid_ref1
$replyemail
And of course you will probably want to tailor the contact.html page according to your tastes and needs. It is a standard web page so whatever you use to create web pages will allow you to customize this page.