I remember passing by a thread or two about de-DRM'ing mobi formats but I'll have to look for them again. Pretty much I have only bought a couple books with DRM so it's not a big deal but if I wanna splurge on a new book it makes it frustrating.
I guess Mobipocket/Amazon figures folks on Linux are more likely to know how to get around their facts of life so why bother supporting the OS's by offering either open source, a fancy browser based app (see Google Reader) or somehow getting generic Linux versions done. Prob with Linux is the wide variety of hardware it runs on seems to make porting not impossible but often it's an adventure. Just happy we have FBReader. Even with the features not yet implemented I like it better then MobiReader or even eReader, though I have to say I really never gave eReader much of a look as MobiReader worked so well on my Clie.
BTW, I'll have to update the pic as I now added the iGo Stowaway BT keyboard to go with...my whole office now fits into a lunch sack...gotta love that...