Currently I know of three clients that make use of or are based on the powersave daemon functionalities:
The graphical KDE front-end to powersave. Works reliable and stable and got extensive testing. Perfect for end-users.
It supports switching between schemes, triggering suspend, shows the current battery level and warns if battery limits are sub-ceeded. It also offers configuration of X-based power functions such as DPMS and screensaver and some more.
The KPowersave daemon is currently maintained by Danny Kukawka (email@example.com)
The graphical Window Maker front-end. Similar functionalities as KPowersave, but slightly restricted due the fact that it is a Window Maker applet.
The WMPowersave client is currently maintained by Holger Macht, who also implemented the client connection stuff in the powersave daemon (firstname.lastname@example.org).
Let the end-user configure most of the variables in /etc/sysconfig/powersave/* graphically. Unfortunately SUSE only of course.
The KPowersave and WMPowersave project are also hosted on the powersave project's sites at http://sourceforge.net/projects/powersave and http://forge.novell.com/modules/xfmod/project/?powersave