On July 25, 2012, Apple released OS X 10.8 Mountain Lion.
We have been testing iScreensaver with the pre-release versions of 10.8, and now that the final version of 10.8 is out, we are pleased to report that iScreensaver Designer works fine on 10.8, and the screen savers built are fully compatible with 10.8.
There are a few minor issues (which are also present in 10.7 and/or 10.6) so please read the “Known Issues” section of the Release notes: http://iscreensaver.com/releaseNotes
If you encounter any issues, please post a question to these forums.