Here’s a short guide for converting a Palm III GPS sled into a normal serial GPS receiver. The Palm III is old tech so its accessories can be picked up cheap and modified for other purposes. The GPS receiver needs to be separated from the Palm specific board and a few components need to be transfered between the two. Once that’s done you should have a standard serial GPS receiver. Here’s a cache in case the “Read” link fails.
[thanks nevamore, who has done this hack with success]