The hype around the iPhone 4S might, you'd think, leave older models like the iPhone 4 and 3GS feeling a little scorned. Think again. You could, for instance, check out a buyback program like eBay's Instant Sale, which has been offering some of the highest amounts around for unwanted iPhones. In fact, eBay sent us this nifty infographic that breaks down the selling frenzy at Instant Sale in the days right after Apple CEO Tim Cook unveiled the iPhone 4S to breathless fans.