I present you, the awesome URLExpander, a plugin for Seesmic Desktop 2 that does just what it says: expands shortened URLs.

This is a copy paste from the description in the marketplace : 

Short URLs are great, but sometimes you don't want to click on a link without knowing where it will take you. If you use this plugin, whenever a post has a bit.ly link in it, it will show you the original URL and the number of clicks on that link.
Works with: bit.ly, 4sq.com, tcrn.ch, nyti.ms, amzn.to, binged.it, huff.to, pep.si, n.pr and j.mp