Yes! http://gonintendo.com/viewstory.php?id=83661
Xbox 360/PS3: They will work in GH:WT and newer GH games.
Wii: No.
http://www.rockband.com/compatibility
No you cannot use The Beatles rock-band instruments to play normal rock band. You must go out and buy the proper instruments.
yep
Yes, Any Guitar Hero controller will work with any Rock Band game.
Guitar Hero.
Yes it does
The instruments are, yes.
No, guitar hero works with band hero, but guitar hero and band hero do not work with rock band and vice versa
You can
Yes.
No. None of the instruments in any RockBand/Guitar Hero are cross platform compatible.
Of course - yo caneven use guitar hero-instruments
i
Yep - theres a full chart here http://www.wired.com/gamelife/2008/11/official-guitar/ I have heard that the guitar hero instruments will not work with Rock Band: Beatles however boo to that