That's exactly what I was looking for. Too bad it's for Sony's Palm OS devices though. I'd rather see something for the more powerful PocketPC devices which have emulators for other systems. I'd love to play C64 games with a joypad hooked up to a PDA.
The GP32 is cool, but a PDA offers so much more software wise. They just need good game controllers. (And the price needs to come down. I hear Dell is releasing a decently priced 300 and 400Mhz PocketPC device later this year.)