Well from now you can tell that the xbox 360 slim has already came out. On the other hand the xbox 720 is gonna be out in 2011-2012 but the design for it is not known all the ones you google are...
You turn on the XBOX plug it in to your router with an ethernet cable (6 bucks at staples)
Select "Xbox Live" then Create account. Fill out the info it requests and then you are done.