well the page giving step by step derections on how to set up mirc is kinda broken at the moment but you can find some info here
http://www.otherpower.com/opchat.html
http://www.otherpower.com/opchat.html#irchelp
if you have mirc downloaded and installed you can just type into the server window
/server otherpower.serveirc.com
then wate for mirc to conect to the server (takes a min) then a gray box that says "mirc favorites" should come up type #otherpower in the top text box and click "join" to the right of that box and that should connect you to #otherpower chatroom
if the mirc favorites box does not come up and you are connected to the server type /join #otherpower
or if you have mozilla browser installed just copy/paste irc://otherpower.serveirc.com/otherpower
into mozilla and chatzilla will open and connect you derectly to #otherpower chatroom automaticly.