I've recently fitted a Biologic iPhone Mount and Case to my bike and I really have to say that they're a top product. The case will fit either a 3G a 3GS or even a 4G and it's just a matter of changing the internal gel inside the case (it all comes in a set) depending on which model you have. The cases are completely watertight and can be swiveled to use either vertically or horizontally. The phone is totally operable through the window, in fact you wouldn't even realize that the phone was set behind another screen. The units are very well made and have a very secure catch, there's no way the phones' ever going to fall out of the case. The case is also made so you are able to charge the phone from the bike battery while riding, so no flat phone battery if you're running a GPS application. Which brings me to something else again..........Metroview, iPhone application, cheap as chips and working so well I don't see myself ever having to lay out for an expensive GPS. All bluetoothed to my Camos headset....working perfectly.............I'm really impressed with the set up.
Just getting back to the Biologic Case...............check out their website and view their video, everything said on the video is true.....they're a great product!!
I'm attaching a couple of pics!