Just finished patching up the Android client I've built and been using for XNA Chat.

There's probably still some bugs in there, and there's more than a couple features missing, but it is fully functional, I use it daily myself.

You can get the latest build here:

https://dl.dropboxusercontent.com/u/9580180/XNAChat%20v1.2.apk

If you use it, let me know what you think/about any bugs or crashes.

It's been pointed out that the XNAChat domain might have expired.
If, for some reason, you can't reach it the following mirror seems to work fine:

http://xna.reedake.com/