Google Voice, is an alternative call apllication to run on smart phones or other devices. Google Voice is now about to hit iPhones by way of an app. This app for the iPhone has immediately access to your contacts.
Here is how it works: you don't press you regular 'Phone' application, but you select your Google Voice button. You just dial a number or select it from your contacts, as you would do in your regular phone application. The App diales out to Google and you' be a called back to connect both sides and you press the Green button. In this way, you do not only skip the standard fees charged to you by your operator, it will also allow you to maintain your calls from any other smartphone or devices. It actually disconnects your telephone number from your device. Additionally, you can also SMS people the same way.