Another good, similar service that just recently appeared is DecentURL. It shortens URLs, and also shows the site you’re going to go to, with a custom subdomain based off of the original URL’s domain, and then a custom piece of text (automatically derived from the page’s title, altough it’s fully customizable).

It doesn’t make the URLs quite as short, but it does usually make them (usually) short enough, and having a descriptive URL is great.

I still use TinyURL, of course, for all the times I really need a super-space-conscious URL.