The recommended and supported PDA is an  HP iPAQ 214.

However, users have reported success with the following devices:

Device NameOS VersionWireless CardScreen Resolution
HP iPAQ 214Windows Mobile 6802.11g640x480
HP iPAQ 614Windows Mobile 6802.11g320x240
HP iPAQ hx4700Windows Mobile 5802.11b640x480
Dell Axim X51vWindows Mobile 5802.11b640x480
HP iPAQ hx4700Windows Pocket PC 2003802.11b640x480
HP iPAQ rx3715Windows Pocket PC 2003802.11b320x240
Fujitsu Siemens LOOX 718Windows Pocket PC 2003802.11b640x480