Research: Mobile Web, handset and mobile ad usage stats

Here are some stats about the mobile web world.

Nielsen Mobile: Critical Mass - The Worldwide State of The Mobile web (July '08)
http://www.nielsenmobile.com/documents/CriticalMass.pdf

AdMob Mobile Metrics Report (May)
http://www.admob.com/marketing/pdf/mobile_metrics_may_08.pdf

The AdMob report of course only measures numbers from their ad network but it's still interessting info and gives some ideas of the trends in the market.