Over at Dubious Quality, they've spotted a really smart thing - a PC utility which allows Guitar Hero practicing, using the Guitar Hero DVD-ROM placed in your PC.

Some of the features of the VGSPlayer? "The Speed control allows you to slow the song down to observe the fast/complex parts in detail. This is done using audio time-stretching, so the overall pitch of the song does not change with the speed... An Animated fret display shows the fret button presses for a given difficulty setting... Optionally, the software can hint early presses for upcoming notes."

Bill at Dubious Quality notes: "This program doesn't support the Guitar Hero controller--yet. You just play along unconnected, but it's still really helpful. However, controller support is listed as a possible future feature. Freaking amazing."