I don't know what systems Palm supports; the alternative systems use various Mobile Windows systems, which support Pocket Fritz - I bought an IPAQ rather than Palm for this reason. You can't import the playable ebooks as such into this, but you can save the introduction-tree as PGN and import that. I've found it more useful to use the ebooks to decide what lines to study, then go to ChessPub.exe and copy the ECO guide(s) as PGN's and import those, thes have much the same material as the playable ebooks, sometimes identical, and you can navigate easily between the the text guides and the game collection. This is great for the train  not to mention Pocket CT art, PGN's of Corus, Linares, etc, delays on the train are no longer a problem!

Have you tried ChessPad?  It allows you to import PGN files, although I confess that I usually just enter the moves manually.  The functions are relatively basic, but it will do the trick when you are on the train.

Regards,
LeeRoth