TinkerTool
If you’re like me then you’re aware of all the default write commands that you can use via Terminal to fine tune Mac OS X. But what if you forget what those commands are? It’s kind of a pain in the ass to Google for all of them sometimes, and you could be on a machine that doesn’t have an Internet connection.
Problem solved with TinkerTool! This is a freeware app that presents you a GUI with the most common hidden options of OS X. It also seems to be frequently updated. Supports OS X versions 10.3.8 and later. And it has a special menu just for Leopard. Check it out!