Yes, free, free, free! Calls will be made via WiFi or 3G connection on your phone. What you need to do is basically download an application called Vonage Mobile for iPhone, iPod Touch, iPad, or on your Android OS! You can then call any of your Facebook friends who have the application through the internet connection.
Depends on how much internet quote you have from your ISP and your Telco monthly plan, this can really be a money saver! I was given about 130 GB per month from my ISP so this app will definitely be a money saver for me if I ever want to make a call to a friend at home! PS: this also works internationally!
Call Facebook friends for free – How it works
According to the video (see it at the bottom this post), your friends need to install the Vonage Mobile app on their mobile device. Vonage Mobile App Supported devices so far:
So who says you cannot make a phone call from iPad? 
Makes me glad too that I’ve ordered an iPhone 4 and decided to give up on my HTC Touch Pro 2 powered by Windows Mobile. Well alright, it seems that the iPad is coming soon but it’s there!
Like the popular Whatsapp application, the Vonage Mobile app will detect automatically your Facebook friends who have the application installed. From the video, it’s also look like the app will even tell you whether your friend is on 3G or WiFi before you make a call. Nifty! If my friend is on 3G, I’m sure he’d prefer me to call him instead of using the Vonage app!
Just watch this video and all your questions will be answered 
If only my iPhone 4 has arrived to test this out….grr..
{ 4 comments… read them below or add one }
This app looks really handy to have. I like how it tells you what data network your friends are running on before you call them. Now if only more of my friends had iPhones
congrats on ordering the iPhone 4. I have been drooling for an iPad SOOO bad! I’ve been hinting to Hubby about it as an early Christmas gift. We’ll see, I suppose
Yeah, the built-in FaceTime doesn’t tell you that so they say it will try to connect and just fail, unlike the Vonage app.
Haha.. hint harder! Any other excuse before December? (anniversary, your birthday or anything?) Waiting for Christmas is a bit too long….
hi mike… don’t forget… this apps can be installed in BB too
Wow really? Cool!