There seems to be a downturn in #vidding chat lately, so I thought I would gently remind my vidding friends that it's there and awesome. Gently. With a chainsaw.

Server: irc.sff.net
Room: #vidding

(borrowing the following from a post by laura47)

If you don't have an IRC client and have java working, you can use the web client here: http://irc.sff.net/

When you enter, it will ask you for a nickname. give it one, hit enter. then type "/join #vidding". you can change your nickname by typing "/NICK vidderface" if you wanted to be vidderface. :-) To send a personal message, type "/msg username message goes here". You can also type "/me loves festivids so much!" to get "vidderface loves festivids so much!"

There are many, many clients for IRC.

I've used http://www.pidgin.im/ which works for many OSes.
Windows has http://www.mirc.com/
Mac OS has http://www.ircle.com/
I use http://www.andchat.net/ on my android phone, and I'm sure iPhones must have a client too.

There are many guides to using IRC. Here is one.