OSCAR (Open Source Cluster Application Resources) from Open Cluster Group
http://www.openclustergroup.org
MOSIX project Website:
http://www.mosix.org
Beowulf project:
http://www.beowulf.org
Oak Ridge Extreame Linux: includes beowulf proj, stone soupercomputer
http://extremelinux.esd.ornl.gov/
Tennessee Oak Ridge Cluster Project (TORC)
http://www.csm.ornl.gov/torc/
Single System Image Clustering
http://ssic-linux.sourceforge.net/
Cluster Computing Resources from the Scalable Computing Laboratory, Ames Lab, Dept. of Energy
http://www.scl.ameslab.gov/
Linux High Availability Project: lots of links to other projects related to Linux Virtual Server Project
http://www.linux-ha.org
Rocks Cluster Managment Tools
http://rocks.npaci.edu/wordpress/
Berkeley Network of Workstations (NOW):
http://now.cs.berkeley.edu/
Berkeley Millennium Project: cluster of clusters project
http://www.millennium.berkeley.edu/
Clustermatic from the Cluster Research Lab at Los Alamos National Lab
http://public.lanl.gov/cluster/index.html
Linux Virtual Server project:
http://www.linuxvirtualserver.org
- Piranha (Red Hat cluster w/load balancing, internode replication, and fault tolerance):
  http://sources.redhat.com/piranha/
Clubmask: Cluster Booting, Management, and Scheduling
http://clubmask.sourceforge.net/
Portable Batch System (Cluster Scheduler)
http://www.openpbs.org/