PDO has announced its new TopSkin and Flipp cases for the upcoming iPhone 3G. The TopSkin is a form-fitting silicone case featuring a play-through design that covers the power, volume, and home buttons in a slim layer of silicone, while cut-outs allow for access to the iPhone’s screen, camera, ring/vibrate switch, speakers, and microphone. The device’s Dock Connector and headphone jack are covered by flaps that can be opened for access…