Apparently it might be possible to make Linux chew on a tethered Pentax DSLR.

http://inside-photography.blogspot.com/2008/07/being-linux-user-can-be-tough-at-times.html

http://forums.dpreview.com/forums/read.asp?forum=1036&message=39004448

http://pktriggercord.sourceforge.net/

http://libregraphicsworld.org/blog/entry/pktriggercord-makes-tethered-shooting-with-pentax-dslr-possible-in-linux

So many fun projects out there!