you might want to try getting an older Palm IIIe or similar, and start with that. There are tons of people on the web doing all sorts with Linux, etc on palms. Robotics, and remote control, .... Older palms, especially common monochrome ones, are very affordable now in the used market, and alot less to cry over if you end up making a paperweight.
Thank you both for your answer. I've look on Ebay for Palm IIIe, and I think there are different models (regarding the memory size). Could you tell me more about that?