I have an Apple 20" Cinema Display and it doesn't have its native resolution (1680 x 1050) in its list of known resolutions. However, the Civ 3 code is actually written really well, so the whole game just works if you change the resolution at one spot in the code. Thus this program.
This was my first Mac OS X program, which I'd previously only made reference to on the DVB introduction page. But someone asked me if they could have it so today (14/03/2004) I decided to clean it up for release and teach myself a bit more about AppKit in the process. That's why it has a half-decent UI (IMHO :)
Oh yeah, to use it, launch it first, then drag the Civilization III application to the well provided. The last resolution in its list is extracted and written into text fields. Change them to whatever you want, hit the Hack button, and you're done! You can change that resolution as many times as you like ... just don't change it to a resolution that's already in the list, as the hacker might get confused. And yes, it is very much recommended to work on a copy of the Civ 3 app (although you can always get it back by reinstalling from the CD of course).
Update 23/1/2005: Sometimes the Hacker will crash when you drag the Civilization III application onto it from a weird location (it crashes before you get a chance to even hit the 'Hack' button). If this happens, first move the Civilization III application onto the Desktop, then try dragging it into the Hacker. That should work.