ZetaWatch is a small OS X program that displays the zfs status in the menu bar, similar to what iStat Menus does for other information. It is far from finished, and due to the current state of libzfs and libzfs_core, changes will be required until the API stabilizes.
This program is copyrighted by me, because I wrote it. This program is licensed under the "3-clause BSD" License. See the BSD.LICENSE.md file for details.