Pi-Sync is what you're looking for. Great program. Linux, Windows, and Zaurus versions are available (and I also compiled it on FreeBSD), and synching between them is very easy.
It consists of various apps, Ko/Pi (organizer), Ka/Pi (address book), Pwm/Pi (password manager), Om/Pi (Email), and KP/Pi (VoIP). These programs saved my Zaurus as I was getting increasingly annoyed with the built-in apps.
