it's not entirely clear what you want to do, but i am assuming you want a user to be able to upload a file via a form which is sent as an attachment to an email via mail().
it's a lot more complicated than an extra header or two, i'm afraid. you have to base64 encode the files and embed them in the email body. you need to set a boundary and mime headers, and content-type and content-disposition headers per attachment.
the simplest way is to go and have a look at http://www.phpclasses.org/browse.html/class/2.html and grab a class that suits your needs.
