I just raved about Google Chrome extensions and, in particular, the Brizzly extension. Well the Bit.ly Chrome extension is also great:

Once the extension is installed, it allows you to easily post to Bitly and access analytics (much like the bookmarklet I have written about)... but the other feature is the seamless inline preview of the URL.

The below screenshot captures a hover on a Bit.ly URL with high-level metrics (total clicks) and links to deeper information. Like Chrome and the other tested extensions, this is lightweight, fast and simple:

bitly extension