Form Field Validation using Ajax, PHP, and MySQL question

Hey guys,

Ajax and jQuery is something I’m new to, but PHP, Javascript, and MySQL I’m pretty well seasoned with.

For starters, I want to create a simple form where there are these fields:

Name (text field)
E-mail (text field)
Zip Code (text field)
Cell Phone Number (text field)
Phone Carrier (dropdown menu)

Thing is, I want to check the database to see if an e-mail address has already been entered. I’d like for that to happen after they enter the email address and tab or click out of the e-mail text field.

For instance, after they enter an e-mail address and tab to the Zip Code field, the script queries the database to see if that e-mail exists already. If it does, it notifies the user and greys out the submit button. If not, they’re allowed to finish filling the form out and submit. It’ll be a huge time saver if this Ajax script is in place.

I don’t expect someone here to create the script, but I would appreciate if someone could point me to a book or tutorial on how to put this into place.

Thanks a ton!

It’s probably not the most layed out tutorial but the general concept is there.