Hi, I've had my iPhone for about 2 days and it's the first one I've ever owned (I got the iPhone 4s). Anyway, I have a 2gb limit on what I can download, but if I'm connected to my WiFi hotspot it doesn't use that limit. I want to only use Skype when I'm at home, and I was just wondering if the Skype app will use my 2gb 3G usage, or if it will use my WiFi? Thanks.