Sun Releases Cluster to the Open Source Community
Sun Microsystems announced it will release the Solaris Cluster source code through the HA community on the OpenSolaris site.
You can find the community here.
Open Source HA
Josh Kuo wrote a nice post combining 2 of my favorite subjects - Open Source and High Availability (HA)
Josh describes implementation options using heartbeat, keepalived, and CARP.