Internet Relay Chat is a tried-and-true broadcast messaging protocol favored
by free and open source software projects. The Linux and Unix Users Group at
Virginia Tech has a relatively active channel,
#vtluug, on OFTC.
Note: You can make sure nobody steals your nick by registering your nick with NickServ. You can register your chosen nick with
/msg nickserv register YourPassword email@example.com
and then you must identify on every login with
/msg nickserv identify YourPassword
We also have a full tutorial for setting up weechat, a common IRC client, on our wiki.