Are you tired of paying expensive phone bills? Then you might want to check out this site and see what it can do for you because it could be just what you are looking for. PhonePower.
com is currently providing VoIP services. Unlike other VSPs they seem to provide more and diversified services. Such as pc2pc, pc2phone, device2phone and then they also have ani/sms/web/wap callback on the same account whilst also providing refillable virtual calling cards for several access numbers. Add to that they have DID incoming numbers, hosted VoIP for businesses and reselling options. All that and they still provide per second billing. So if you want to have great communication opportunities and yet save big bucks, you should check out this site. 
