Phone Power is a VOIP service that allows you to place Internet-based phone calls to the US, Canada and abroad. All you need is a piece of equipment in your house or office that routes all your incoming and outgoing calls over the Internet. The services also offers feature like call forwarding, number portability, call blocking, and more. Calls to US and Canada are always free, and you also get 20 free hours of international calls per month with every plan.
Phone Power call rates
http://www.phonepower.com/