So, it seems our wonderful friend Arminius2 has managed to finally get his IM client working. He has uploaded an early test version, which does infact work nearly flawlessly (over WiFi, I have not tried over EDGE, but I don't see why it wouldn't). Very basic functionality so far, no buddy groups, just your list in alphabetical order. Sending messages works flawlessly, you just have to tap the line entry when you bring up the keyboard.
You can grab it over at http://code.google.com/p/apolloim/
And make sure to thank him and whoever else worked on the project, as this is one of the major programs the community has been waiting for.