The forum's official IRC channel is #python-forum
If you're a first time IRC user, you can use freenode's webchat at http://webchat.freenode.net/
to drop in and say hello.
If you plan on using IRC regularly, using a proper IRC client is recommended.
My preferred clients are irssi
on linux and X-Chat 2
on windows, but if you don't like those, finding an alternative shouldn't be hard.
There's usually someone in the channel, but we don't always talk/pay attention.
So don' get discouraged if no one answers you when you say hi, it could take us a few minutes(sometimes longer) to notice you.