Arya: This feature was already in Tiger, just not enabled by default. Don't u see the Path button of Tiger toolbar

. Its there since ages, Mac came with it first, see Mac OS X leopard also supports ZFS, just that you cannot use it. There is only one library file of ZFS, You cannot mout or work via GUI, you can work only via CLI. If you have a file saved in a ZFS partition it won't start but ZFS is there....even though it is in useless form.
Hey arya, Windows Vista also has support for Ext3 partition using UNIX services for Windows, just not there by default