Get GTA IV Soundtrack Via Cellphones

Rockstar has teamed up with Amazon to bring digital downloads of GTA IV’s radio tracks to players, using protagonist Niko’s cellphone and the newly announced Rockstar Social Club as delivery methods.
It works like this: when you hear a song you like, send a text message via Niko’s virtual cellphone to a “ZiT” number.
Amazon will then build a custom playlist of the songs you want, assuming you’re a member of the Social Club.