Google Wave is a new, free product from Google that combines email and chat. I love it.
This video is 80 minutes long, but it describes all the features I know about.
Unfortunately, if you're not in America, you can't sign up for it.
However, I found a workaround.
Get someone to invite you, and go to America and accept it. That's what I did when I was in Atlantic City last week for VisWeek 09.
I guess once you log into it in America, it just figures you're an American travelling abroad when you come back to Canada, or what have you. I'm in Ottawa, and wave is working great!