The leading photo sharing site, flickr.com, charts the popularity of the cameras used by its membership. Recently the Apple iPhone has jumped into a virtual tie for first place with the Canon XTi. Furthermore, flickr states on its "Camera Finder" page that it can only detect the camera used about 2/3rds of the time, and that, therefore, cameraphones are under-represented on the graphs. Yikes.
(Click on the image to see it larger.)
(Thanks to Dennis Ng)