First I’ll give a link to my pastebins and then explain - http://pastebin.com/u/Strider64
There are five files (pastebins) that are necessary to get the registration form working, but it’s still not the full working code. It will take some tweaking on your end in order to get it working, but that’s the fun of coding isn’t it? 
Anyways, I will from time to time go back and update the comments, add some more pastebins to it. I will freely answers questions, but remember I’m doing this for free. So keep this in mind when developing your own registration form and that I’m doing other things that will prevent me from answering questions in a timely manner. Though they probably will be answered in a couple of days on the average, but it might be longer it all depends on how busy I am. I didn’t post this in the tutorial section for the simple reason I’m not giving step-by-step instructions and for the most part you’re on your own in figuring on how to incorporate the scripts.
P.S. The Members.php class isn’t finish and I know some methods(functions) are left hanging. ;D