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.
How to Build a Remote Kill Switch
Learn how to build a wireless controller to kill power when things go... sentient.
Wireless Joystick Hookup Guide
A hookup guide for the SparkFun Wireless Joystick Kit.
Understanding Thermal Resistance
Discussing what thermal resistance is, how it’s used for thermal management, and how to maximize the life of your project.
smôl Power Board LiPo 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 LiPo.