other then the left trigger everything is very straight forward on a rock band controller (heck they tell you a lot of the buttons and dpad stuff right on the board). I didn’t say this in my last post but I have played street fighter 4 with the rock band guitar and it works, I’ve also played halo 3 with one of the xbox 360 guitar hero guitars.
here is a very poorly done outline of the rockband controllers pins.
the pins under the other button pins is the same thing as pressing the upper ones one only with a strum down (im pretty sure it was a while since i last tested it).
the Left trigger is an analog control but there are ways to make it just a plane button
as for the regular guitar hero one, if you have ever played halo 3 with it you will notice that you always turn left unless you hold down the strum bar. this can be easily fixed since it is probably just like the rockband guitar and has a simple switch with a spring, if you take out the spring and just turn it all the way right it should work fine, though you will have a worthless wire hanging about inside your box.