Reducing Arduino Power Consumption
Contributors:
Alex the Giant
Alex the Giant 
Resources and Going Further
More information on low-power modes and options can be found in the datasheet for the 328P.
For more power-related fun, check out the following SparkFun tutorials.
Blynk Board Project Guide
A series of Blynk projects you can set up on the Blynk Board without ever re-programming it.
Beefcake Relay Control Hookup Guide
This is a guide for assembling and basic use of the Beefcake Relay Control board
Hobby Servo Tutorial
Servos are motors that allow you to accurately control the rotation of the output shaft, opening up all kinds of possibilities for robotics and other projects.
smôl Power Board AAA Hookup Guide
Small in size, small on current draw. It's a smôl world! This guide will get you up and running with the smôl Power Board AAA.