Make Unlimited Free Calls on Your Cellphone with Google Voice

"The idea is that if you only use Google Voice to send and receive calls—and you set Google Voice so that it only displays your Google Voice number when it rings, all of your calls will be free, and you may never need to use another minute again. Each carrier is different, so we're looking at what each plan looks like, and how to use it with Google Voice to get free calls."

[via lifehacker]