There is also a build made by Adam Michel which builds ppc and intel via
http://firefoxmac.furbism.com/
He also supports nightly builds.

@matt lew: plus the author said on his blog that he doesn't have time anymore the update the ppc version.

This is such a winner!

IMHO, this is what Firefox for Mac should have beem from the beginning.
It has the look and feel of a real Mac application. The Aqua-look HTML elements are very well integrated. (Just like Camino.) And all Firefox themes and extensions work perfectly. I just wish there was a theme with an unified toolbar. (But maybe I'm just wishing too much...)
There are separate versions for PowerPC and Intel Macs, which are lighter (and faster!) than the official Universal Binary version of Firefox.
This is really great! Keep the good work.

They're not the same. The other one specifically says it's PPC optimised. This one says Intel.