I currently own an iPhone 4 (skipped iPhone 4S), but my contract doesn't xpire until June of 2013. My wife has an old Nokia. Yeah, I know what you're thinking. I was thinking of giving her my iPhone 4 and purchasing a iPhone 5 on her line because her runs out around October. We want to keep our numbers. Would it be possible to switch SIM cards like that? I know it seems complicated. Thanx in advance.