I have to credit Al F. as the reason that I found this program. About 2 years ago, Al asked me if I knew of any way he could connect to our UNIX server from his Treo via SSH. Wow, connected to a UNIX shell from anywhere? Too sweet. So, after a little research I found PSSH.
PSSH is a very lightweight program for Palm OS that allows you to SSH into your server. It has proven invaluable to me. One time, I even fixed a user's mail quota problem from the beach!
The downside to PSSH is how small the font in, even at its largest. But, in a pinch, this program can save you.
BTW, check out my ode to the Treo in last year's Philadelphia City Paper. You have to scroll down a little.