While I am still working on a “feature story” of MacOS X accounting packages, this is a resource for those desiring to setup GnuCash on a Mac.
This approach uses Fink. I personally prefer DarwinPorts, but so far there’s no GnuCash port there. It should, however, be possible (albeit not as trivial) to compile GnuCash without installing Fink. Just make sure that you’ve got all of the required dependencies (most, if not all, of them are available through ports).