I posted a blog on how to shortening the URL using the TinyURL and KrunchURLin few weeks ago, I believe these are the more common use and famous by providing the URL shortening.
But actually I do find out there are plenty of web site which may help you to do itfor free. Some of them even provide the bookmarking features, some are difference in term of the lenght of the url they allow to hide.
The following are some example that I found on the internet:
Ruby URL
URL Cut
TubeURL
Shorl
Fhurl
dwarfURL
doiop
Zip My URL
Yep It
URL Snub
SNIP URL
moo url
Metamark
Easy URL
Dom. IR
A2N
