OpenSolaris 2008.11 is currently the latest community operating system release from Sun Microsystems, but by this summer it will be released with OpenSolaris 2009.06. OpenSolaris is updated in a six-month release cycle, but the next release name is being called OpenSolaris 2009.06 and will ideally make it out by the end of May.
A preview release of OpenSolaris 2009.06 can be found at
Genunix and is based upon the Solaris Express Community Edition 106a code-base. The announcement of the 2009.06 name can be found
here. Hopefully this next OpenSolaris release is able to improve the
AMD Opteron performance.