Budget Billing

I don't know if this one actually saves you money so much as making how much you need available for bills each month more predictable.  Dominion North Carolina Power offers a service called budget billing, which means they average your past 12 power bills and just bill you that same amount every month.  This way, you don't have those large upswings in summer and winter.  I just started it this month, so I'll let you know how I like it.  It was easy to sign up for, right on my account page on the website.  They do reevaluate their average every 4-6months, so it's not a free for all for leaving all the lights on either;)