For those of you who haven't tried using the ps2 controller on guitar hero II, here are the controlls:

L2: Green
L1: Red
R1: Yellow
R2: Blue
X: Orange
Left analog stick: whammy bar (doesn't really work as good as the real whammy bar)

By the way, nothing strums, so don't press the buttons freely, pressing them is just like strumming the note!

Go to practice and choose any section of any song. Put it on any speed (preferably slowest) and play it. Then, right at the end, unplug the controller and plug it back in. The fretboard should keep moving endlessly. Then go to quickplay and play that song. It should only have the section you practiced with playing and the rest is nothing else. This glitch lets you get 5 stars on any song, but may take a few tries.

Go into career mode after unlocking the grim reaper and select him as your character. Next restart your PS2 and go back in to career mode and choose any song. The grim reaper will be playing the guitar you start the game with.

To play with Grim Ripper's wicked scythe guitar with any player, simply change your character to the Ripper, make sure you have his scythe as your selected guitar, and then change to whomever you wish to play as. You will keep the scythe until you change guitars again. If you do change guitars, get the scythe back by being the Grim Ripper again and choosing it.