Living room rock gods, take note: the battle of the bands is on, and this time the arena is portable. Electronic Arts, MTV Games, and Harmonix have finally launched Rock Band for the iPhone, challenging Tapulous's monopoly in the "rhythm music" space currently cornered by the popular Tap Tap Revenge series.

For $9.99, iPhone users can shred solo to the likes of AFI, Pixies, Foo Fighters, and Blondie, or connect up to four phones via Bluetooth connections to create subway car quartets jamming Steve Miller Band's "Take The Money And Run." The game has 20 songs pre-loaded, with more songs available via in-app purchases (a tantalizing feature for both user and app developer).

Like its game room equivalent, Rock Band for iPhone allows users to choose between guitar, drums, bass or vocals, but vocals are (oddly) performed through tapping rather than singing into the phones mic. Push notifications will allow friends to invite you to jam sessions, and an in-game message center allows you to check your bands' status. The app also integrates Facebook Connect, another avenue users can take to invite friends into the game.

Naturally, Rock Band's goal is to take some share away from Tapulous, whose apps are installed on more than a third of iPhones. But it doesn't end there. Activision Blizzard has yet to adapt Guitar Hero, the console game that took rhythm music games to super-stardom, to the iPhone. Meanwhile, Tapulous released its own update, Tap Tap Revenge 3, two weeks ago.

With all three game makers targeting the same audience, the competition should be as fierce and challenging as the guitar breakdown at the end of Beastie Boys' "Sabotage." Try not to miss your subway stop.

[VentureBeat, Washington Post]