What a cool idea.
From the site:
In a nutshell, GOP.AM is an online tool for converting really long website addresses into short ones so that you can share them with your friends via Twitter, IRC, Email, Campfire, etc.
There is not much to add, but I think this is a really good idea.
To test this baby out, follow this link to come back to this entry: http://gop.am/RUVw
It even gives you stats!
Original URL Length: 80 characters
GOP.AM URL Length: 18 characters
Shortened By: 62 characters
The number of sites is not infinite, so use wisely. I only grab one to check it out. There is also an abuse feature to prevent spamming or illegal use. I have to give props to Michael Steele for giving a thumbs up to this great tool.