Spotlight, the built-in search feature in OS X, is a handy system-wide service that combines powerful search capabilities with an easy-to use interface.
Screen shot courtesy of Coyote Moon, Inc.
One of the reasons that Spotlight is a cinch to use is that it doesn't have any advanced options to clutter up the interface. Just type the word or phrase you're looking for, and Spotlight does the rest. But that doesn't mean you can't use advanced search techniques, such as Boolean operators; just add them to your search phrase.
For tips on refining your Spotlight search phrases, take a look at: