The latest stable release is 2013.11, which can be downloaded here:
buildroot-2013.11.tar.gz (PGP signature) or buildroot-2013.11.tar.bz2 (PGP signature).
The latest release candidate is 2014.02-rc3, which can be downloaded here:
buildroot-2014.02-rc3.tar.gz (PGP signature) or buildroot-2014.02-rc3.tar.bz2 (PGP signature).
This and earlier releases (and their PGP signatures) 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.