Actually, in case you didn't know it, Linux for Palm handhelds exists. It was released about two months ago, I think. I don't remember the address, but search for linux @ http://www.palmgear.com and I guess you'll find it
It does exist but only for Palm III's if I recall. I don't know how much that is going to change. If you really want linux on a pda you should buy a linux pda. I know that sounds gimpy but as you have to change the rom (at least I would think) its not going to be cheap to change your palm either. I know some you can upgrade there rom's (like the palm III's I think) so maybe those can be upgraded to linux by someone.