So the cool tool of the day is WebShell (ssh for iPhone), but we couldn't get it working yesterday when we installed it.
The answer wasn't RTFM, but on the forum indirectly. Like most people, I run ssh on a non-standard port. You need to change webshell.py to look like this (replacing 22 with whatever you use instead of the default port 22):
[nethope@server WebShell-0.9.5]$ grep ssh webshell.py
cmd = 'ssh -p 22'
help = "set shell command (default: ssh localhost)")
The original line is just cmd = 'ssh', and that's where you make the change.