I am using the Arduino Duemilanove and tring to reduce the power consumed by it as much as possible. I brought the current down to around 12 mA by putting the Duemianove in its lowest power consuming sleep mode. I then reduced the current even more by bypassing the Voltage regulator. It is now using 2.5 mA in sleep mode. I need the current to be in the micro Amp range. Is there anything that can be disabled that would reduce the power even more.
Read the relevant chapter in the ATmega8 data sheet. You might also consider using a version of the Arduino without the USB driver onboard like the Arduino Pro Mini or such.