Still no invite.

My main question is, how do you add songs you purchase on the device? Do you have to buy an mp3 from Amazon, download it to the Xoom, then add it to the Music app? How does that work? If that's the case it'd have to be WAY better than Amazon, cause the's kinda a pain considering Amazon I can buy/add new songs with one click, and the space doesn't even count against my quota.