I remember reading on the Ubuntu forums some time ago about a program to automatically check configuration changes into version control for you. It was (of course) not Ubuntu-specific. I'm pretty sure it used Git, though it may have been Subversion, or perhaps even able to work with multiple different VCSs. My googling has turned up nothing, and I'd rather not roll my own script if someone has already done this well.
Of course I could just manually check things in, but there are reasons I'd like it done automatically. (I'm actually planning to use this for my LastSession.plist file for Safari, so when the #@$%^*&! thing crashes, and I don't restore everything, and then Leopard crashes, the fact that it has such lousy session management won't mean I lose the dozens of windows with dozens of tabs I had open.)