Howdy,
Your Palm III will work fine for datalogging. You can get the software for free (MMcd) from
http://mmcdlogger.sourceforge.net/ However, I think the current version is 1.8g I have a copy I could email you if you can't find it. As for the cable, I made one out of a CAT5 cable, Dsub connector, and a diode. works great. If you are on a real budget crunch and have an old laptop you can run the palm emulator using MMcd. The cable for the laptop is slightly diffrent but I can show you how it's made.
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