Rockstar's Social Club is Live!

They'll probably let you do it soon enough, in the edit profile section of the site. Just a guess though.

I think it's more likely to be done from the game itself, like EA do with FIFA, where you enter your email and password to link them.

Sorry that I used EA in a GTA sentence =(

Remember, it is technically "Pre-Registration"

I'm not certain on this, but I imagine that R* is doing a pre-registration to seed their database and get an early take on community size. This will help them make sure they have enough servers and bandwidth on the 29th to make the experience worthwhile. I'm sure they think they'll get a lot, and have probably planned for a lot, but as MSFT proved over Christmas, you never have enough hardware.

If they are doing this, there is no reason to take all of the profile information that they will eventually require. Since the Zit and stat tracking services aren't live, they don't need no stinkin' Gamertag or Amazon.com account information right now. I expect that the profile will significantly expand on the 29th as the rest of the site's functionality roles out.

Yeah, member numbers started at 10000. They're past 30,000 now, 20 thousand registered in just a few hours!

Flash sites fail, Hard. I mean granted you can make things move and look pretty. But at the cost of speed and effectiveness. i hope the "Main part" of the site isnt flash...

try deleting your cookies and restarting?