I recently downloaded the Facebook App for Android onto my HP Slate 7 tablet, and I saw that it gives you the option to "Free Call" your friends when you're both on mobile devices. I was just wondering; is it really free? Even if you're both in different countries? Because I have a friend in America (I live in the UK) who I would really like to chat with from time to time. :3 I thought that maybe it could charge my phone number, which I have in my account details. I dunno though. So, please, if anyone could help, I would be very grateful. 