Aaah, found the instructions on the development repository website: http://pkg.opensolaris.org/dev/en/index.shtml
Seems pretty simple: "To switch your system to the in-development release of OpenSolaris (the "dev" release), you can issue the following commands: $ pfexec pkg set-publisher -O http://pkg.opensolaris.org/dev opensolaris.org $ pfexec pkg image-update" -- This message posted from opensolaris.org