This is a great tool - worth watching the 8 minute silent film - watch it in HQ if you can or the scripts will be illegible. "This video demonstrates basic interfacing between Squeak Etoys and a PIC16F877A MCU."
One of the best things about BEAM robotics is that you can
get started without buying any bits at all-- you can just go
rooting around for "techno-trash". These are some good
sources of salvage