Tunewear has introduced a variety of new cases for the iPhone 3G. Icewear for iPhone 3G is a form-fitting clear case made from high-density silicone, and features ribbed sides for added grip and open access to all ports and controls. It sells for $25. Tuneshell for iPhone 3G is a clear, snap-on hard polycarbonate case featuring a smooth surface and open access to all ports and controls. It is priced at $25. Tuneshell Plus for iPhone 3G is another…