FreeCulture.org has an IRC channel at #freeculture on irc.freenode.net
Learn how to join Free Culture's IRC channel using gaim.
Here a tutorial about how to use IRC with irssi and screen.
If you use MacOSX, read a tutorial for installing and using Colloquy. When it says to join #adium, join #freeculture instead.
If your school attempts to block IRC, there are ways around an IRC block.