waypath and google have nifty little bookmarklets that let you run a search based on the page/highlighted text. I turned them into a block. Drupal's not letting me post the html for you (what tags to I have to put it inside?) -- you can see the block at http://speakcyb.org/anize and get the html by viewing the page source.

There's also a module in development to list links from waypath at the end of nodes, but that was a little more advanced than I needed.