Started using this nifty little Firefox addon recently. Long URL Please automatically expands all shortened URLs into their original links. This addon can replace the shortened URLs in all Webpages and is especially useful if your are a 
Twitter user. If you prefer Opera then you can just drag Long URL please bookmarklet available on their website to Opera’s bookmark bar [also applicable in Firefox] .
The conversion of the URL is performed using by routing the page request through Google App Engine. It currently supports up to 32 URL shortening services and has also released its API. One of the neatest Firefox addons IMO.
If you are a fan of Greasemonkey, then you can use the LongURL Mobile Expander script that shows you the original URL when you hover your mouse over the shortened link. It also has a Firefox addon version.
Godspeed
http://www.shubhspace.com/2009/01/turn-shortened-urls-into-original-links.html#links