I woud like to know where to find power usage info myself. (Been using unix shells for over 20 years.) The Openmoko Freerunner provides quite a bit of power information, such as voltage, current, temperature, and capacity for the battery. The battery current is negative when charging. Most of this information is in various subdirectories in /sys/devices/platform The n900 has plenty of directories in /sys/devices/platform, but I haven't found any power status yet.