With some considerable fanfare, Electronic Arts and Harmonix released the latest version of Rock Band (iTunes link) today -- it's now a US$9.99 iPhone app with in-game song purchasing enabled. Your initial investment gets you a very familiar looking game experience with 20 songs included (from Lynyrd Synyrd, Foo Fighters, Blink-182, and The Beastie Boys among others) and support for Bluetooth-enabled four player games. Gameplay is exactly what you'd expect -- you tap the buttons at the bottom of the screen in time with the music -- but is it going to be enough to pull people away from the thoroughly entrenched iPhone-native music experience Tap Tap Revenge? While Rock Band may have the might of its brand to help raise awareness, iPhone gamers have been delighted by the Tap Tap games for more than a year now, plus it the incredibly popular Tap Tap Revenge 3 can be downloaded for just $0.99.

Early user reviews on iTunes have been mixed, with a number of users complaining about the price (naturally, all $9.99 games suffer through that at first) but an increasing number comparing it very favorably to the PSP game, Rock Band Unplugged.

Like its big brothers on other platforms, Rock Band on the iPhone features a music store where new songs can be purchased for $0.99. At launch this store includes songs from OK Go, Lenny Kravitz, Social Distortion, Devo and more. As we post this story the top five downloads are "Today" by Smashing Pumpkins, "The Kill" by 30 Seconds to Mars, "This Is A Call" by Foo Fighters, "Funk #49" by James Gang and "I Was Wrong" by Social Distortion.