Avast PDA is available for mobile devices running on the Palm OS

avast! PDA 4
Manufacturer: ALWIL Software
Version: 4

Avast! 4 PDA puts mobile security in the palm of your hands, but is only a decent software solution compared to our other reviewed products. Avast PDA is available for mobile devices running on the Palm OS, which is a feature not usually available with most of the other software we reviewed.
Effectiveness: Good

Avast’s mobile security is limited to antivirus protection. The PDA edition doesn’t incorporate firewall settings, spam reduction tools, or a quarantine section. And Avast PDA doesn’t run in realtime.
Features: Good

Because the PDA edition of Avast 4 doesn’t run in realtime, there is more user input required to scan and protect your device from mobile viruses. Users can view an activity log reporting scan results, but only on the Palm version. The integrated log viewer was not included in the Windows Mobile edition to minimize the product size. That being said, Avast is clearly concerned with not leaving a large footprint on your phone’s memory, and uses minimal resources to preserve the speed of your device.
Ease of Use: Very Good

Avast 4 PDA has an upfront interface and clear-cut navigation, which is great since you have to use it to perform on-demand scans. The user experience is further enhanced by the program speed. A typical scan of the whole phone only takes a few seconds.
Installation & Updates: Excellent

Avast is loaded onto your pocket device by using a PC application. Updates can be sent to the phone directly over GPRS and is designed to be small enough to facilitate speed and low impact. Updating the device is also possible when syncing it to the host computer.
Technical Help/Support: Very Good

Avast has some options for getting help online, through a FAQs section and even user forums. You can also submit requests through email. However, not only is online chatting unavailable, you cannot get live assistance or support over the phone.
Summary:

Avast 4 PDA is an alright security solution, but lacks features and is primarily intended for the Palm operating system. While this is a decent solution for Palm protection from viruses, if you're looking for more protection on other mobile devices, it is probably in your best interest to look at Kaspersky Mobile Security, BullGuard Mobile Antivirus, or Norton Smartphone Security.