If you already use Gmail, you know about the excellent Auto-Complete feature in the address book. Google just went one step ahead and implemented Auto-Complete in the google search engine itself, this is of course stillk beta, but is accessible through this link or through Google Labs.
Just type anything in the search bar, and google suggests searches, including how many results such a search would bring.
Via Scoble and Google Labs (which is a web site you should check periodically if you like those stuff).