This single key launch application creates a catalog of frequently performed searches and tasks. Assign shortcut keys to frequently performed actions and frequently opened files, folders and applications. It’s more than Spotlight (the live search feature built into OS X since 10.4) on steroids. It’s like a mini-Finder and Spotlight in one.
Some users even report that it works faster than Spotlight. A December 2007 Lifehacker interview revealed that the current developer does not have plans to take Quicksilver much further, but since the program is open source, anyone can ride to the rescue. For now though, you can download the latest version here.