It's called Zapper, and while it's only available in beta form right now, it's already a mighty useful tool. Like Sherlock, Zapper gives you a lot of freedom in creating custom search channels of your own. But what first impressed me about Zapper is the way it works. You can pop it open as a little window on top of whatever else you're doing, but you don't have to. Instead, you can just select some text in a browser, word processor or other program, then hold the control key and right-click the text.
Zapper appears, with the text in the search window.
With the mouse, you pick which search channel you want to use. Hit enter, and a browser window pops open with the search results. It gets better. Zapper uses a special algorithm that reads the words surrounding the text you asked to search. It tries to understand the context of your search request, and to reject pages that use those words in a different context.