You can now download the Boss Battle pack on XBLM for FREE, as of now, the pack isn't on PSN
but we'll see what PSN Thursday brings.

These songs are now playable outside of career mode, so yes its some what boring because you probably all ready played them
but hey, there free!

Songs in the pack
"Devil Went Down to Georgia"
as made famous by The Charlie Daniels Band,
"Original Composition by Slash" As performed by Slash,
"Original Composition by Tom Morello" As performed by Tom Morello.