
Informationweek followsup on their previous quote that ZFS was not on Leopard. Croll, senior director of Mac OS X Product Marketing, clarifies:
"ZFS is not the default file system for Leopard. We are exploring it as a file system option for high-end storage systems with really large storage. As a result, we have included ZFS -- a read-only copy of ZFS -- in Leopard."
This means that Leopard will be able to read ZFS volumes... assuming there was a way to create one on Mac OS X, which there isn't... yet.