Stumbled across a neat site the other day while in an IRC chat called Pastebin. A contributor wanted people to review his source code so he put it out on a site called http://pastebin.ca
The site is designed so that you can post, comment and retrieve someone's source code for review. The site also offers a way to comment and highlight the code. There are various levels of control from a completely public area to a username/password option to view a post. Pastebin also offers to expire the post based on a time period of your choosing.
In short, a easy quick online collaboration tool.