I am not sure what types of uninterruptible power supplies (UPS) this works with, but I know it works with my two APC Back-UPS ES 725 devices and OS 10.4.2. I decided to finally hook them into the computer, so my computers will know to shut down if the UPS is on low power -- I hadn't hooked them up since I moved and upgraded to Tiger.
I downloaded the APC software, but before I installed it, I noticed a battery icon in the menu bar which linked to the Energy Saver control panel. There was now a new option, in addition to Power Adapter, called UPS. This gave me the standard Energy Saver settings, plus three options from which I can mix and match:
Mac OS X Hints
http://hints.macworld.com/article.php?story=20050817215930870