Broadcasting gameplay from one computer to another?
Solution 1:
If you want to broadcast your game play over the internet, take a look at Justin.tv (http://www.justin.tv). Unfortunately I haven't hosted any live gaming sessions on it, but I watch a lot of games using the site. The game play appears smooth and does not display any lag. This video shows how to set up your computer for broadcasting WoW.
A lot of people use it so I think it would be a good choice. If you only want to share your desktop on a LAN, this might not be suitable.