MacTeX is a product produced by the MacTeX TeXnical working group of the TeX Users Group (TUG). It is the Mac component of the TeX Collection DVD, the reference edition of TeX distributed by TeX User Groups across the world. The reference edition runs on Mac OS X, Windows, GNU/Linux, various BSD Unix systems, and most other computer architectures.
The MacTeX Distribution is available on CTAN or on the TeX Collection DVD (free with membership of TUG or with many of the other Users Groups around the world). Redistribution of files from the MacTeX collection should be done with care after reading the License restrictions by copyright holders.
MacTeX consists of two pieces: MacTeX-2008 and MacTeXtras. MacTeX-2008 is an install package which installs everything needed to run TeX on Mac OS X. The package uses Apple's standard installer; installation takes four to eight minutes and is automatic. MacTeXtras is a collection of optional extras: Additional Front Ends, Spell Checkers, Documentation, and Showcase items.