The rest of the story...
The full story emerged on Tuesday: apparently the executive misspoke. Leopard will support two file systems, the HFS+ technology currently found in Mac OS X, as well as ZFS, a next-generation file system developed by Sun and unveiled in 2005. However, HFS+ will remain the default option.
At some point, Apple will likely make ZFS the default file system for Mac OS X, but Sun hasn't even gotten around to doing that yet for Solaris 10. These transitions can take years.