As one of the most impressive-looking iPhone accessories featured in The Free iPod Book 3.0, Belkin's Sport Armband for iPhone ($30, also known as Armband for iPhone) is a water-resistant, hand-washable neoprene and clear plastic armband for the iPhone. With reflective edging on its face and a mini (gym locker-sized, not car- or house-sized) key pocket on its side, the Sport Armband has a Velcro-coated armstrap with a metal O ring for proper bicep…