You can boot from LIVE CD and follow the instructions in the below mentioned link. Once you have booted from LIVE CD you have to open a terminal and set the Opensoris partition to the active partition, modify the menu.lst file as described in this document and reboot from hard-disk.
http://hub.opensolaris.org/bin/view/Community+Group+documentation/Installing-OpenSolaris-on-New-Partition -- This message posted from opensolaris.org
