Note: Please excuse the huge lack of documentation. However, this is a pre-release due to the very large amount of requests I've been getting for a copy of this script. This is still very beta and I have plans on making this a much more developer friendly and easier to install script. My true desire in the end is to make this as much plug 'n play as possible. With that said, please do not make foul remarks or complain about the unfriendliness of putting it together.
On a slightly more positive note, I believe there is enough information for any intermediate to expert developer to get this going. Heck, even those seeking to learn ajax for the first time shouldn't have too hard of a time figuring out the ins and outs of what's going on in this ajax contact form. Just read line by line and follow function to function, it will all come together.
For those wanting to at least know 'some' information on what they can do right away... take all the contents you received in this zip file and upload it to a subdirectory of your website in the same manner of which it was unzipped (keep directory structure the same).
Open up scripts/contact.php & scripts/xmlHttpRequest.php. Change the four variables in each accordingly, then upload back to server
Then, go ahead and access this page on your site: http://www.example.com/path/to/ajax/index.php and try it out.