If you want to make this easy, use <a href="https://github.com/socketstream/socketstream" rel="nofollow">https://github.com/socketstream/socketstream</a>. Great progress is being made on the 0.3 version and it makes pub/sub broadcasting and message pushing very easy. You wouldn't be the first person to make a live multiplayer HTML5 game with it: <a href="https://github.com/alz/socketracer" rel="nofollow">https://github.com/alz/socketracer</a>.
Buried source as a mediafire link? Author needs to learn about github.<p>Code itself is pretty difficult to read and quickly pasted together, but otherwise a decent example on how to tie the technologies involved together.
To install socket.io you need only execute `npm install socket.io`<p>This installs socket.io from the npm registry (there is no need to download/extract the zip).