MacTeX is a complete, easy-to-install TeX distribution for MacOS X on both PPC and Intel platforms. The .zip file is an install package for Apple's installer. The package contains all of TeX live 2012, with some GUI applications, a recent version of Ghostscript and the convert program from ImageMagick.

Beware: the download is large (over 2 Gbytes).

See also mactextras.

The author is TUG TWG-MacTeX.