SpeedFindX

SpeedFindX is a Mac OS X only application that searches for files on all currently mounted and formerly mounted drives.

It has a great set of features and an intuitive, user-friendly interface, It's a very powerful and extremely fast tool. SpeedFindX uses the locate database from within Mac OS X's core unix OS to retrieve the search results. The size of searches results are un-limited.
What's new in this version:
Fixes to the GUI & speed improvements for cacheing information.