This has already been done well.
I wasn't aware of the LiveRider posted by tdmac above. That looks like a cheaper solution for the casual biker.
However, as tethernaut already stated, the iBike Dash is about to be released, and it does everything that this patent could cover, and more. In fact, I doubt that iBikeSports (
http://www.ibikesports.com/) hasn't already patented their product and its features. They have been in business for a while and are pros at the products that they make. I've had an iBike computer (the iAero) for over a year now and I love it. It gives me the following data for every ride: bike speed, wind speed, cadence, altitude, grade of the road, heart rate, temperature, and the amount of power I'm putting into the bike.
The new iBike Dash is a bit pricier than the LiveRider device, but I think it's well worth the price. It includes an extra battery to increase the life of the iPhone while being used in this manner to at least 5 hours, or more if you buy more batteries. And, the iBikeDash has a plastic clear cover, so the iPhone/iPod touch never gets wet.
Furthermore, the iBike Dash overcomes the two major shortcomings of the previous iBike computers: GPS and storage space. Now all your rides can be mapped while including the eight sets of data I mentioned above (if you get the iBike Dash + Power), and the largest ride that can be stored is 6,000,000 miles, instead of about 10 hours.
(I'm not associated with iBikeSports at all. I'm just a pleased customer.)