If you're wanting to be more mobile with your Windows Phone and biking (pedal or motor driven type) is cup of tea, look at Arkon's Handlebar Mount with Water Resistant Holder. It's not a bad way to bring your Windows Phone along for the ride.
The Arkon's advantage over carrying your Windows Phone in a belt case is that it allows you to view your phone while on the go (e.g. to view maps, music player, etc.) without taking a hand off the handle bars.
The Arkon Handlebar Mount is a two piece design. First you have the handlebar mount that fits handles up to 33mm in diameter. From motorcycles to bicycles to ATVs the Arkon Mount can fit a wide range of vehicles. The mount comes with two rubber strips that can be used to help with a more solid fit and to prevent the Mount from scratching up the handlebars. The mount is fitted with a ball and socket connector that has a tension screw to allow you to fine tune the holder/case's positioning.
The holder or case itself is made of thick rubber with a zipper that connects the front with the back halves. The zipper is firm which helps keep moisture away from your Windows Phone. The case has a thick, clear plastic face. A small cutout rests at the base of the case where headphone cords can sneak out.
On the back of the Arkon case is the mounting plate that slides on to the Mount. A brass set screw is present to prevent the case from bouncing off the mount.
The back half of the Arkon case is padded and to help add more padding (if necessary) the case comes with two foam inserts that will slide behind your Windows Phone (if there's room). The Arkon case is just large enough to handle the HTC Titan. The Samsung Focus S fits nicely with room to spare and the Focus Flash is swallowed up by the case.
As far as performance is concerned, the Arkon case mounted easily with two screws on either end of the mount. The case slides into place with a snap and the set screw is large enough to put into place easily as well.
The case stays in place nicely on a bicycle. You did have a bit of bounce but not enough to give concern that your Windows Phone was about to bounce off the pavement. The plastic face is thick enough to protect your phone but thin enough to allow your screen to remain touch sensitive. The screen is sensitive enough for big button taps (Zune player controls, slide to unlock, tap to launch, etc.) but typing can be frustrating.
It it possible to manipulate the buttons on your Windows Phone when it is snug in the case. The thick plastic does make viewing the screen a little challenging. You can make out navigational maps and Caller ID but I don't know if I'd worry about reading any lengthy emails while the phone is in the case. Then again, you shouldn't be typing while riding a bike.
With regards to water resistance, the Arkon gets high marks. The zipper seal is tight enough to keep moisture out but I wouldn't have the dual zippers meet at the top. There is a small, pin hole gap where these two zippers heads meet that could let some moisture in. Move the meeting point to the side and your weather seal improves.
The headphone port is at the bottom and shouldn't be an issue. Keep in mind the Arkon is water resistant, not water proof. It's not intended to be submerged but rather survive a rain shower while your out on your bike. While you could mount the Arkon on a waverunner or personal watercraft I have my doubts that your Windows Phone would survive the first outing.
All in all, the Arkon Handlebar Mount with Water Resistant Holder performed nicely. It allows your Windows Phone to be functional and accessible while running around on your motorcycle or bicycle. The thick plastic face of the case does make it challenging to view the screen but does help keep things dry. If you won't be using your Windows Phone for navigation, a Bluetooth headset and a secure belt case might be a better option. But if you need to view your Windows Phone while on the open road, the Arkon should do alright.
The Arkon Handlebar Mount and Holder is currently running $18.95 and you can find it here at the WPCentral Accessory Store.