I did the jailbreak dance last night and installed MobileTerminal using Cydia. The app loads but then just shows a black/blank screen. Turns out the problem as noted in a comment on the wiki is the colors are set to black on black.
To fix this, install OpenSSH using Cydia and then ssh into your phone and delete the following file:
The next time you start MobileTerminal it will rebuild the prefs and use defaults that let you see what’s happening.