The Atlas Releases are installed below /cern/atlas/dist. (If you have an opinion about where they should be, let me know.)
Currently, we have 10.0.1 and 10.0.4. These were installed using PacMan and are the versions for SL3 (Scientific Linux 3).
To setup a release, source the script setup.sh in /cern/atlas/dist/N.N.N
-- TDR - 20 Sep 2005