That seems to be the scuttlebutt, based on information from various execs at Sun. Apparently Apple’s been so interested in ZFS because they’re planning on making it the default filesystem in OS X Leopard (10.5).
When I first heard that Apple was interested in ZFS, I hoped and prayed that it would come to this. I’m still fervently hoping that Apple really is planning on making ZFS “the” Mac OS X filesystem, because even though HFS+ works, I’ve still never really been entirely comfortable with it. Honestly, ZFS won’t really buy much for the average joe for things like laptops or other single-drive systems, outside of the amazingly better data integrity checking that’s built in, but for multi-drive systems, I think ZFS will really come into its own. A Mac Pro with four 750GB or 1TB hard drives installed is the perfect place for ZFS to be used for both speed and redundancy.
I’m definitely interested to see what will actually come out during the WWDC about Leopard.