Open UT when you are connected to the internet.
To join #planetunreal do the following:
Multiplayer > Find Internet games
Click on the "Chat" tab
Enter "#planetunreal" (without quotes) in the box at the top and then click on the button there.
It will take you to a room, which is #planetunreal.
To join a game someone else is in do the following:
Double click on the person's name, that will bring up a tab with their name on it.
Click on their tab
Type a message and it will automatically respond if they are in game
Responses: The IP for the game they are in. Blue underlined link, click on it to join their game
Local game: that means they are playing offline
No response: They aren't in game, chat away!
In menus : this means they're twiddling with UT, I think.
Hope that helps
[PuF]Rezz
Quasimodo's Lair
overshadowed by assertion makes me certain - skinny puppy