I just saw the BBtv post about Mark's guitar amp, and thought I'd share my similar project. It's also based on the LM386 although the circuit is a little different (and sounds way better).Link
To save time and cost for anyone wanting to make this amp I offer either a bare PCB, or a simple parts kit (including PCB). This is available at my online store. There are also some video examples of the Minty Amp in action.