facebook verify like email from user (double opt in like)

hi! Then i need a form, where the user puts in their email that they use on facebook so i can match up and give them credit on my site once they hit the like button. They process is: Sign up (they have already done) go to page, fill form (you can use as much php as you need, and embed in file i will include_) you build form, do jquery ajax post to self. Post should set the user option some how so when i get the user data i can tell if they have liked. It should also set a session variable, facebook_liked to true. don't ask for more than 15.