MacCentral has an news story which reports that Quake III Team Arena may have Mac OS X support.
"The mission pack CD will actually have builds for Mac, Linux and Win32. We'll see if we can stick some OS/X action in there as well."
Not a very strong statement. :) The next question is when everyone will be able to start using Mac OS X. WWDC is in one week, so we should hear some OS X news soon.