[NutmegCarrera]

I think the word "Guitar Hero" is o.k., but I'd be surprised if you could use their logo.
Depends on whether it's a registered trademark or not. Similar to the word "Coke" vs. the word written in the font used for advertising. A company can register several different versions, each with a trademark. If the "R" symbol isnt there - they have less success enforcing infringement - I think, anyway.