Vonage has just announced today that their mobile app for the iPhone and BlackBerry is now available for download.

This app will allow users to make international calls over both WiFi and AT&T’s cellular network. Of course, you’re going to be paying for both AT&T minutes and Vonage’s rates if you don’t use over WiFi but by year’s end Vonage hopes to give those who subscribe to their $25 a month World plan unlimited calling as opposed to the current pay-per-go model.