There is an IRC for WordPress and WPMS. Join #wordpress on irc.freenode.net with your favourite IRC client.
It is useful because people can answer your question more quickly and interactively, so it might be fruitful to ask there first or simultaneously with a posted question on the WPMS Forums. If you do so, posting a link to the forum question in the irc channel would be convenient for others.
The channel is logged, so mind what you say if you mind that others might mind what you say.