Because my last attempt at an IRC gateway was "a bit" hard to install and to change (the gateway started the server and communicated using stdin/stdout, so one couldn't change the gateway while the server was running), I made a new one. This time, I added a feature to the engine to support it:
New cvar: log_dest_udp - contains a space separated list of IP addresses and ports to send all console output to (in the same format as QW rcon data)
Basically, my IRC gateway now is an external process that uses rcon to retrieve log_dest_udp from the server, adds itself to the list and uses rcon to send the changed value to the server (yes, this does have a race condition, but should usually not be an issue... as a workaround, one can regularily request that cvar and add oneself to it when needed, but my gateway is not doing this yet). Then it can see all console messages, and use rcon to talk to the server. So setting it up is much easier now - just point it to some Nexuiz server with a rcon password, and that's it.
It already supports color codes, special fonts, chat in both direction, and a somewhat clumsy but simple way to add plugins. The RBI KH server already uses the new gateway (that you can watch it on irc.oftc.net, #Nexuiz-Pwayers isn't a secret any more anyway). A newly added feature is notification about free player slots.
I'll release it shortly after the next Nexuiz release, which will be a minor one and quite soon.