The Yocto Project development team makes the Yocto Project available through a number of methods:
Releases: Stable, tested releases are available through http://downloads.yoctoproject.org/releases/yocto/.
Nightly Builds: These releases are available at http://autobuilder.yoctoproject.org/nightly. These builds include Yocto Project releases, meta-toolchain tarball installation scripts, and experimental builds.
Yocto Project Website: You can find releases of the Yocto Project and supported BSPs at the Yocto Project website. Along with these downloads, you can find lots of other information at this site.