So, there's this command line thing
defaults that lets you change the default settings for certain programs that register their defaults using it, you can access through the terminal, which is sweet, but I'd like a UI for it.
Anyone have one?
You want Property List Editor, which is part of Apple's developer tools. You can install them from your 10.6 DVD. You might also be interested in Secrets, which is a prefpane that gives you access to many of the common edits people do with defaults write. There are also a few 3rd party apps that do the same thing as Apple's application, although I recommend Apple's.