GameSpot has posted a new preview of the URBZ. It's a bit different from the usual stuff; it's in the form of a visitor's guide, so you know where to go and who you can meet, amongst other things. So far just the three shown districts, 125th Street, Gasonline Row and Central Station are explained. There's also an introduction page, where the next bit is from:

"Don't let yourself be spotted as an outsider--learn the moves and use 'em right to win the night. Staring up at the skyscrapers like you've never seen the city before will brand you as a tourist. But knowing the right greeting or how to jive with the folks in your local district makes all the difference between getting access and getting locked out."

So for the ins and outs of the three districts, go to the URBZ City Guide.