Luckily, OffRoadGeek copied down all of the following from the old devnet board:
That gives you all the programs and maps you'll need.
As a note, zRoadMap relies on gpsd. I couldn't find a version of gpsd that was compiled for the zaurus except the version that comes with qpegps. So, I've always installed both programs and when I want to use gps, I start with qpegps, then launch zroadmap when I have gpsd up and I've obtained a signal.
As a note, one of the drawbacks to the zaurus is that none of these programs can give good directions to you. They can tell you where you are, what street is coming up as you drive, etc., but can't provide you with a "best way from a to z".