Free phone calls with the application NetTalk iPhone :

Here is a low-cost VoIP player, NetTalk.com, which currently offers a free software through iTunes which will allow iPhone users, iPod touch, and iPad free calls to U.S. and Canada and that even using the function conference call. This service can be used with Wi-Fi, 3G or EDGE. You just need to register for a free account to take advantage of this service. The small catch is that you can not receive calls because you can not assign a real phone number for this application. The intelligence service is free as 411 conference calls and technical support and not forgetting the import contacts from your iPhone.