Fur.ly is a URL shortener, like goo.gl or tiny.url, but what is nice about Fur.ly is that it lets you link multiple web sites to a single URL. This is great for teachers who want to send student a bunch of links.
Enter the URL (web site address) in the box and click "go". It's that simple.
Krunchd is another site that does this also.
Google URL Shortener - lots of great features
Krunchd - make one link to multiple sites