Mobipocket PDA and ubuntu

[Linda Hanigan]

I bought my husband a palm z22. I installed J-pilot and got it working
with my husbands palm so it will synch. 
Now he still needs additional stuff to do paperless geocaching. Maybe
someone here can help me figure it out. Option one is to download a
mobipocket ebook format file. My understanding is that I have to somehow
get a mobipocket reader installed on the PDA and then you just synch the
files to the pda that you want to read.
I think I know how to do the file part, but how would I get the
mobipocket reader installed on the palm? Has anyone done this?
Am I right that if you have the reader on the PDA you just have to put
the files on the PDA or do they have to be formated by the pc before
transfer in some way?
                     Thanks
                     Linda