DevonThing freeware: "EasyFind is an alternative to or supplement of Sherlock and finds files, folders or contents in any file without the need for indexing -- and therefore immediately. This is especially useful if you are tired of slow or impossible indexing, outdated or corrupted indices or if you are just looking for missing features like case sensitive or insensitive search, boolean operators, wildcards or searching for phrases."
Update 7/15/09: Six years later EasyFind is no longer an alternative to the long forgotten OS X Sherlock. It's an alternative to Spotlight. Recommended universally, if you download it do pay attention to the ReadMe file. There's no associated Help file (it's free), so the ReadMe is where you learn about syntax and search. I filed it in one of Document folders.