Looks like they've updated the man page for new work before it is available.
This feature is not in any version of Solaris 10. I don't know when it is scheduled to appear. It is a portion of the project Crossbow and gives zones separate access to the IP layer (rather than only at the TCP layer).
It is present in at least nevada build 61, so you could play with this feature in any version of Solaris Express with that build or higher.
My guess is that this will be backported into Solaris 10, but someone on that project would likely need to talk about the timeline for that. You might ask on the project discussion board.
http://www.opensolaris.org/jive/forum.jspa?forumID=110
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Darren
I opened a case with Sun Support. After two escalations they basically said (paraphrasing) 'Oh, did we release that documentation already?'
The features will be in the Solaris 10 7/07 release, and in the Solaris Express 5/07 release.
It has been part of OpenSolaris since January of this year.