One of the coolest MIDP applets I have seen in a long time is MidpSSH.

With this free applet you can connect via ssh to just about any unix server from your mobile phone. They have a range of versions for both MIDP 1.0 and 2.0 phones, where you can select the features you want to conserve memory. The MIDP 1 version with ssh1 lite build worked on my ancient Nokia 6610 phone. However I tested it on my wife’s LG U8120 3G Phone with the full MIDP 2.0 version.

This is great it has full support for ansi colored text as seen in linux directory listings. I was able to connect to one of my servers at a reasonable speed via 3G. The usefulness of this would be enhanced by writing macros for common tasks. This you can do on the phone. Typically I would imagine you would use this for remote monitoring and emergency work on a server while youre on the road, so it would be good to setup an emergency tool kit of macros to help you out.