I'm sure this document will prove very useful to people considering moving from Solaris 10 to Solaris 11. It details taking an existing JumpStart server, installing the Oracle Solaris 11 Provisioning Assistant for Oracle Solaris 10 on it, creating and configuring an installation service, and then provisioning a client system using that installation service.
It is important to point out one limitation with the Provisioning Assistant which I'm sure a lot of people will miss:
Note: Once you have a system that is running Oracle Solaris 11, this system should subsequently be used as a server to provision future Oracle Solaris 11 updates, because there are no plans to extend the functionality of the Oracle Solaris 11 Provisioning Assistant for Oracle Solaris 10 to support provisioning Oracle Solaris 11.1.
— How to Use an Existing Oracle Solaris 10 JumpStart Server to Provision Oracle Solaris 11 11/11