Expermimental mono builds of AdiIRC for Linux/OSX.
You need mono installed, and probably some libmono librarys (in Linux). Mono is a port of .NET for other platforms.
If you have problems with fonts or menues, download this file and save it as /home/youruser/.fonts.conf
Please use the ticket system if you have any problems.
Ps. I only test this in Ubuntu, but should work on most dists, if the mono libs are installed.
It is mostly useless on OS X, seems like their Windows.Forms drawing is really slow atm, hope this gets better at some point.
Pps. Yes I know this is not a native linux/osx app, and there are better alternatives, but people have requested a version for this, and its fun to see how good it can run :)