There are several aspects to Zaurus security.
Firstly, keeping someone with physical access to it from easily getting control. Secondly, ensuring that when it's on a network, an outsider can't break into it!
The Zaurus is a very flexible device when it comes to networking, not just 802.11 wireless networks but also bluetooth, GSM/GPRS/EDGE (and probably, soon 3G).
- Securing Bluetooth*