AltPhone application enables your iPhone to call anywhere in the world at very low calling rates. You may even save on your local airtime charges, by either using the AltPhone VoIP capability (over WiFi or 3G), or by the AltPhone taking advantage of some mobile plan features (i.e., unlimited incoming calls or unlimited calling with a favourite number). AltPhone is a self-contained service, you don't need to deal with a service provider or sign a contract - just download and instantly activate the AltPhone, and start calling. Your AltPhone account will be credited with some funds to help you get familiar with using the AltPhone service. Then, you'll be able to top up your account directly from the AltPhone application.