Untile we figure out a way to interface this thing with the empeg, I'm stuck with the StreetFinder software as the only way I can get any use out of it.

The Palm connector is a serial port, basically you should just need to figure out:
-pin mapping. I felt lucky with Google
-where to power it

I assume it already does RS232 pullup from TTL, so that should be it. And if not, well, underpowered serial port signal shouldn't cause you any problem, it just won't *do* anything.