http://www.andchat.net/
If you don't have market access there is a download version on site.
http://www.yaaic.org/
Same here, version on site
http://www.countercultured.net/android/ - no download here but there is an emai address, some developers will mail apk
And finally a blog post comparing http://blog.lassey.us/2010/06/25/android-irc-clients/