Here's another browser extension that I've found handy. This one places a context menu entry called "Google It" into the right-click menu for Internet Explorer. You can highlight any text on a page, right-click, choose "Google It", and it brings up a new window with the search results for the text you highlighted. Nothing fancy, but I use it all the time. This script will set it up:
Google It Setup
(right-click, Save Target As..., click to install.)
Once again, Internet Explorer on Windows machines only.