First off you want to install kitchen sync, http://www.handhelds.org/~zecke/kitchensync.html it takes a while but I got it to run on 9.1 with no real problems, a few dependancies that were easily solved. Once running set up kitchen sync, you will need to select the Sharp ROM sync, I have not tried this as I use OZ so you might stop here
Plug in you Z, always plug in turned on, it tends to crash if you try and power whilst in the cradle. I found it helps to press the sync button on the cradle, it might open the port or something. Now ping the IP of your Z. If no luck run an ifconfig from the console, check you have usb0 interface up (I messed about in the MCC to bring this up at boot) If you can ping run kitchen sync and the message window should say something about a connection established, it should sync now. If you are having problems check /var/log/messages when you plug your Z into the cradle to make sure it is running with the right driver/device config.
It took a while of messing about but I have got it working. You can not install new apps to the Z from kitchen sync, but once you have a connection you can ftp into the Z and install the ipk's onto a card or RAM and install from there. I did find it easier to create an entry in the hosts file for 'Z', saves typing the IP address all the time.