Over time, they're converging. That said, though,
- opensolaris, as expressed in Project Indiana and released Monday as opensolaris 2008.05, is to be DESKTOP centric that just happens to have a server-grade kernel, stack, and kick-butt file system; and
- solaris, also cost fee, remaining (foreseeably) a SERVER and HOST centric platform for Sun's big-ticket commercial wares.
The code base is converging, where...
- The best stuff of [classic] solaris was out ported to opensolaris (e.g. SMP kernel, virtualization, ZFS, etc);
- The good (and familiar) stuff from the open source community embraced (e.g. X.org, gnome, cups, etc.) in opensolaris; and
- The best of embraced open source community stuff converged back.
/S