Internet Relay Chat (IRC) is a group chat room. Useful for when you need more real-time communication than the mailing list can provide. It can be thought of as Twitter for old timers.
You can join us at #boston.pm on irc.perl.org. A handful of Boston.pm members regularly monitor the room.
To use IRC you'll need an IRC client or an IM client that supports the IRC protocol. One such multi-platform client is Pidgin.