Share Web 2.0

I am a web design student and I have to set up an ecommerce site. I have the shopping cart thing down, but I would like to set it up so each person can create there own login/account. I really have no idea how to do this. Can someone help me out please?

It looks to me like jonaskevin and nickjonas are really them. Joe doesn’t seem to have one. Is it true or are they just really good fakes? They should post on the JB twitter and say if it is really them or not!

What I want to do is take my friends list on facebook and see which ones have a twitter account. I have everyone on facebook not my msn or yahoo account so it makes it realy hard to find out who I know has twitter??? HELP!

Someone is getting into my facebook and myspace accounts and blocking people and erasing messages. This is a personal vendetta and not a typical interent hacker… I’ve changed pwords and emails on file with both accounts. What else could I do?