If you own an iPad, you don’t even need your phone to use it.

A new mobile application created by Vonage, the Internet telephone company, enables anyone owning an iPad or iPhone to make phone calls to their Facebook friends for free. The iPhone application was released yesterday, while the iPad application release is said to be just a few short weeks away.

The application, known as Vonage Mobile for Facebook, is free to download and free to use. This release of the app works on Wi-Fi, 3G and 4G, while future versions are planned to include instant messaging and SMS.

As neat as the new app may sound, it does pose a few worries. For instance, currently there is no way to block anyone on your Facebook friend’s list from making phone calls; which leads to the question: do you really want everyone on your friend’s list to be able to call you? Most of us have accepted invites from relatively unknowns – friends of friends or people with shared common interests. While having them on Facebook isn’t a worry, taking it to the next level may be something we aren’t quite prepared to do.

Another concern is, if this becomes the app they hope it does, how will it affect mobile networks and their minute plans? Of course, using the app will still cost in data usage (versus minutes), so it could be that this is just the beginnings of a whole new world of mobile calling.