[Update 2011-11-15] Most of the following is obsolete, due to Google having shut down its real-time search, at least for now. But see my later post for something even easier.
Here's a handy little thing I just noticed. Suppose you are somewhat tempted to click a link posted by some guy on the Twitter, but you're uneasy about clicking that shortened URL. (And you've forgotten to bookmark one of those handy posts that tell you how to preview shortened URLs.)
Solution: Open a new tab or window, Google the twitterer's name, and then click the "Updates" link in the left column of the Google results. That's it.
More details and example screen shots below. Click 'em to big 'em.
As you'll observe, there are more normal-looking links there in the tweets, and Google tells you the site on which the linked-to item resides.
Sadly, hovering over the link does not give what we'd like: the full URL in the status bar (bottom bar of the browser). Instead, as you'll note, you see some encoded URL that Google evidently uses for its own internal purposes. (When you click it, it does take you to the proper place, though.)
On the other hand, I'd bet that clicking this link sends you through some redirect process, part of which would be Google checking the safety of the link and possibly warning you off of it. You've seen something like this before, I'm sure:
Anyway, a minor thing, but maybe you'll find it useful.