http://bitly.com/r6YMh7
Vonage Time to Call is a free iPhone app for placing international calls from your iPhone. One of the big differences between Time to Call and other solutions is the call quality. It's also one of the few calling solutions that allow you to call remote extensions and even conference bridge lines in other countries. While the app is free, there are fees for placing the calls that vary by location. There's also no special calling card codes or other confusing dialing requirements in order to place the call. Most locations are currently $1.99 per call, but some countries may have a higher associated fee. All calls are billed to your iTunes account.
