The latest stable release is 2013.11, which can be downloaded here:
This and earlier releases can always be downloaded from http://buildroot.net/downloads/.
You can also obtain Daily Snapshots of the latest Buildroot source tree if you want to to follow development, but cannot or do not wish to use Git.
Copyright © 1999-2005 Erik Andersen,
2006-2013 The Buildroot developers
Mail all comments, insults, suggestions and bribes to
The Buildroot developers email@example.com