For those who pay too much for international calls Vonage launched Vonage Mobile, offering low-cost international calling for the iPhone and iPod touch. This appl allows calls to be made via Wi-Fi or cellular connection, while the iPod touch application is apparently limited to Wi-Fi calling only.
Vonage Mobile is easy to use - you can call around the world from home, a Wi-Fi hotspot, or while traveling around the country. There are no access numbers or new phone numbers to give to friends and family. Simply enter an international number or select a contact from the existing contacts on your iPhone and press send. iPhone users calling international numbers via the Vonage Mobile application on a cellular network are automatically connected to Vonage's network and utilize only domestic airtime minutes on their carrier while paying Vonage's international rates for the calls from a prepaid, automatically refillable account. This app will give customers exceptional per-minute rates to any country they want to dial.
Vonage Mobile for Iphone and Ipod is already in the App Store and it is offered for free.