This one is private free stuff so is OK
Just found an app called "Text Now" (I have Android, not sure about iPhone) that give regular-quality phone calls over wifi. For some of the guys that pay by-the-minute or have long-distance charges, it will save you a fortune.
You will need to get a new phone number for the app, but its a 2-minute sign-up and they give you a local-area-code number. The neat part with this one is you can call land-line phones, or cell phones that DONT have it installed, works like regular cell service.
I installed it on Friday night, and SO FAR, no intrusive ads either.