Ian Murdock has blogged additional details about Project Indiana
. Murdock goes into detail about some of the existing problems with Solaris/OpenSolaris that inhibit a pleasant end-user experience especially if going to OpenSolaris from Linux. What essentially Project Indiana boils down to is trying to take the best of both the Linux and Solaris worlds and merging it into one under an OpenSolaris name, which more than likely will be licensed under the GPLv3.
Therefore, what you will be left with is DTrace, ZFS, Zones, backwards compatibility and other great Solaris benefits along with some Linux bells and whistles like great package management. Don't try to go download "Project Indiana" quite yet as it's not ready. However, a indiana-discuss
mailing list has been setup to discuss Sun's recent efforts. Ian is keen on making Solaris the better Linux than Linux.