BlueTerm - BSD - blueterm.zip (Contains jar/jad + readme/license + J2ME source)
After searching for a long time to find something like this, I eventually gave up and hacked up my own.
This is very simple, but very useful. The name comes from the fact that it is a bluetooth terminal for your phone (only tested on a Series 40 Nokia). Connects to a bluetooth device and allows you to send input, and then displays output on a basic VT100 terminal.
Combined with getty this allows you to bluetooth into a Linux box and get a login prompt, for details see the readme.txt. :D
Known bug: Due to the thread usage (and no locks I guess), if the terminal needs to resize its buffer in memory and the bluetooth thread is receiving data fast enough this will cause it to write to the buffer before it is resized. On my Nokia 6234 this causes it to run out of memory and restart. I have only seen this happen twice (I was running aafire ;P), but use at your own risk.