As usual, you can get the release from the download page!
For those upgrading from 2009.06 or 2009.11, see the 2009.12 release letter for more detailed information about new features etc.
As before noted for the 2009.11 release, ATK-DFT 2009.12 is not a complete replacement of ATK 2008.10, as it is still missing a few key features. Therefore it is considered an alpha-version, while VNL hereby is released in another beta-version.
This version is known not to function on Redhat-compatible Linux distributions (CentOS, Scientific Linux, etc), due to an older version of GLIBC. Specific builds for these distributions are expected to be released during 2010. We have however confirmed that this version (and earlier ones) of ATK runs on Fedora 12, thanks to recent updates in their distribution.