Guitar Hero instruments compatible with Rock Band?

Are Guitar Hero instrument controllers compatible with Rock Band games on the Wii?My brother picked up a Band Hero game.. a copy of the game AND a drumset, guitar, and mic! A complete set! (Isn't Band Hero about a year old though?)So I want to know if they can work with the Rock Band games on the Wii, especially the recently released Rock Band 3!

I've been hearing stories that they aren't compatible regardless of console...CHeck gamefaqs via question answer section or the forums, make an account and ask their, someone would know for sure.