very simple, yet can't think how.

Hi everyone, Sorry for the n00bie question but I've been racking my brain, searching Google and yes, I have been "RTFM" for over 6 months :-) All I'm trying to do is set up a "User system" that allows a member to create their own personal site using an auto_increment type system? This is my problem... I've been trying to look through other code trying to figure out where and how they do it - but for some reason I can't figure out how to Dynamically create something like this: User Joe comes in and creates an account... when he creates his account he can give his site a TITLE, DESCRIPTION, ABOUT US INFO (say /aboutus.php), CONTACT (./contactus.php), etc. after he clicks "Submit" the system automatically creates a site such as _http://mydomain.com/0/joe/ _ (http://mydomain.com/0/joe/ ) , Bob does the same thing and his is _http://mydomain.com/0/bob_ (http://mydomain.com/0/bob) I'm sure most of you know how this is done or you've seen it on sites such as Soundclick.com (although it's CF) - I've been checking out Jamroom to see if I could figure it out there- but kinda got lost lol... I want to use PHP, Smarty and MySQL to do this - but I'm missing something... I'm not asking anybody to build this - I'm looking for a little guidance, tips, etc. - that's all. Would this be done through auto_increment in MySQL or something? Thanks everyone :-)