I've just done some stats on iPhone usage over the last year on one of our Internet Yellow Pages sites and can see a few interesting points:
1 - iPhone users use their phones for search all through the day in a pretty similar curve to desktop users BUT during lunch hours their usage goes down instead of up. Looks as though people do lunchtime browsing on desktops if they have their lunch with them, but iPhone users maybe give their phone a little break (down 20% from expected curve) over the lunch hour (probably have less need to spend "their" time doing search, just use the bosses time!)
2 - There are obvious sections that vary from the pattern described in point 1 (such as takeaway food which peaks 7-8PM with an almost bell curve either side for 4 hours; although the bell curve is interupted by a mini surge between 11PM and 1AM) - and the types of things people look for on an iPhone isn't as varied as desktop users (in an IYP sense) but strangely, even though many things are time critical there's a very similar usage pattern to the desktop (looks as though this is an early predictor for mobile actually living up to the promise it has always had).
3 - The service areas that you want to look at for mobile are Food, Health and Automotive - other areas are represented but not nearly as much.
Nothing groundbreaking there, but it might be worthwhile discussing how mobile is developing for people in different sectors - to keep specifics down to a minimum let's state if what we do is local or nonlocal and a service or product so puncture repair would be refered to as a local service etc...