MacTerminal is my favorite:
(Aw, crap, that link is going to die in a couple months when MobileMe iDisk goes away... I'll have to find a new domain host to move all my "random pictures to" before then.)
Sometime this week, when I have a free evening, I'll boot up the Linux server (the rack-mount monstrosity underneath - a quad Itanium rig,) and the Mac 128 and MacTerminal over and try that URL on the Mac-cum-serial-terminal. Unfortunately, my serial terminal boot disk for the Apple IIc died, and I can't get ADTPro to work on the Linux box properly.