Google voice is a telecommunications service that uses software technology to improve the process of managing the way you receive calls. If your mother wants to give you a call she has to figure out you where you are at the time she is calling. Are you at work, at home, or out on the road? With Google Voice a caller can reach all three of those numbers -- home, work, and cell -- simultaneously by calling a single number -- the Google Voice number.
FREE USA calling and It is 1 cent per minute Canadian calling.
You can make international calls too.
You get 1$ free credit when switching over.