Phage is name of the first virus that attacks Palm, and other Palm OS based devices.
When executed, the Phage virus fills the screen of the PalmOS based device with a dark gray box, terminates the application that is running and replicates itself (infects) other installed applications.
By most accounts, Phage is the first virus that is capable of infecting PDAs, or "Personal Digital Assistants", unlike several other well documented Trojans.
Phage is will also affect PDAs manufactured by Handspring (Visor), IBM (Workpad), TRG, and Symbol Technologies.
A PDA gets infected when Phage spreads from one Palm to another if infected files are shared via IR beaming or via "Hot Synching". At this time it does not appear that Phage can propogate itself (although it would be a cool hack to have Phage automatically enable beaming, and transfer itself to nearby Palms - I've thought of writing something like this since my Sony MagicCap days, and virii do not have to be destructive...).
The best solution to Phage, in the absence of proper anti-virus software is to completely restore the Palm OS device by means of using the HotSync manager. Set all HotSync conduits to "Desktop overwrites Handheld" and HotSynch with the Palm desktop.
Note that default settings for Palm OS backups does not include applications, so unless this setting has reset by the user, all installed applications will have to be re-installed.