Powersave Applet consists of a script, that does various tips and tricks from Intel's PowerTop and lesswatts.org to reduce power consumption while your laptop is on battery. There is also an applet that provides a nice status icon in Gnome or KDE.
Automatic session locker for KDE. Requires Python (2.3 and higher), PyKDE, PyQT, python-bluez to run. This small script will lock desktop if monitored device becomes unavailable. When device becomes available again - script will unlock desktop.