Yeah, as wikipedia says:
Harmonix faced difficulty in making the Xbox 360 guitar wireless, as developers are charged a licensing fee to use Microsoft's wireless technology. If Harmonix chose to pay the fee, the Xbox 360 and Playstation 3 bundles of Rock Band would have sold at different price points. Instead, Harmonix elected to choose a wired technology for the Xbox 360 bundle's guitar.
So, anybody know how it's charged?

Flow -"The important is to pwn other ppl"







