doesn't really work. You can find it here:
http://www.redsaurus.net/00/ - don't come running for help though. It uses the GTK toolkit, which needs X11 on OS X. That means that it's not a native OS X port, so everything looks and works differently. If you get it working in the first place, that is. I have tried to install it several times, and it never worked.
On top of that, I don't know if you can shoehorn it into editing Quake 1 maps, although there usually are ways to do that.
I think our best bet is Warrens new editor. It looks very promising, and the progress he has made in the past weeks is rather impressive.
For what it's worth, I myself am working with the fitzquake source to get it to compile on OS X (and later on, linux) so that we have a decent engine to work with.