Updated only slightly in shape for the iPhone 3G, PDO's TopSkin for iPhone 3G ($20) is a simple silicone rubber case with an included film protector, detachable ratcheting belt clip, and substantial coverage for the device's body. Flaps on the top and bottom cover the headphone and Dock Connector ports, and button covers are included for all of the iPhone 3G's controls save for the Ringer switch; it, along with the camera, speakers, and microphone…