You may remember our previous work with Go Know that resulted in the Go Observe software members were using with Palm Pilots. (mymassp.com)
The standard for EPUB apparently remains the ugliness of Palm Pilots circa 1998. (epubsecrets.com)
Primarily used on Palm Pilot devices; but software readers are available for PalmOS, Symbian OS, Windows Mobile Pocket PC / Smartphone, desktop Windows, and Macintosh. (formatbookinword.com)