"Top Gun ssh is an ssh (version 1) client for palmtops running Palm OS and having a TCP/IP stack. This includes the Palm Pilot Pro, Palm III, Palm V, and the corresponding models of Workpad and Visor. It does not include the Palm VII; that machine apparently has no way to do TCP/IP."
"pssh is a free, open-source SSH 2 client for Palm OS. It runs on handhelds with Palm OS 5, an ARM processor, and a 320x320 or larger high-resolution screen."
Supports SSHv2. Source code available. Based in part on OpenSSH.
"TuSSH is an SSH client for Palm OS devices. It should now work with any device with Palm OS 4 or greater. It might even work with OS 3.5 devices but no testing or support is planned for these devices."
Supports SSHv1 and partially supports SSHv2. Free for use, but no source available.