I have long dream of mounting my iPhone 3GS onto the bike. For cycling it can be used as a GPS(Motion X-GPS Sport), an iPod, a walkie-talkie(Phone), a camera, etc. Functionality it's even better than Garmin Edge, besides top model Edge 705 comes with heart rate detector and cadence meter, which is not essentials to me.
Most iPhone bike mount in the market come at a price. iBikemount produce very nice bike mount which cost USD29.99 excluding shipment.
http://www.ibikemount.com/?utm_source=EveryTrail&utm_medium=Banner&utm_campaign=EveryTrail_Banner

Today while shopping in the mall I came across this RM18 half silicon half plastic hybrid case. I put my iPhone + NexxOne Polyshield into the fishbone. Wallap! It's a 100% fit.



Back at home I found some Velcro and rubber strip from the storeroom. I prefer Velcro because I own more than one bike. It will be easier to move the bike mount to another bike later on. If you have only one bike, you might consider using cable tie instead. All these materials can be found at local hardware store.

Here's the 123 steps DIY iPhone bike mount.
Step 1 – Cut the velcro to desire width and length.

Step 2 – Most stem will have a gap as shown in the picture. I use a thick rubber strip to cover the gap.





Step 3 – Secure the fishbone and stem with Velcro.


Finish!


When needed, just pull the top and slide the iPhone out.

Done! Time for me to get a backup battery (Griffin Reserver Battery) and A2DP Bluetooth stereo headset.