Here is a good tutorial for a contact form:
http://www.phpeasystep.com/phptu/8.html
Contact forms are allowed on x10Hosting.
Thats an okay contact form.
But if a user gets antsy about the time it takes for the server to post the file, they may hit the submit button alot, sending you ALOT of unwanted emails.
Id suggest looking up javascript submit disable.
So that onClick of Submit it becomes disabled.
Just alittle advice, i did it on an old contact form i had.
because that same thing happened.