Found this project through the SS Guitar BBS:

Little Rebel Home Page

Make sure to check out the sound samples at the bottom of the page.

The site is in German, but is easy to get the gist of it.

Layout, Schematic, & Specs

It is a great deal more complicated than the Noisy Cricket that Duhvoodooman posted. Like most complicated, PCB-based projects, the hardest part is coming up with the finished PCB.

tung