Comscore has surveyed close to 40 000 US cell phone subscribers and, according to FierceDeveloper, published these February 2009 stats.
As can be seen from the numbers, Windows Mobile holds a significant share of the installed base, and is well ahead of archrival the iPhone. Its seems there is a pretty large gap between market share and mindshare. Something developers may want to bear in mind when planning their development platforms.
Read more at FierceDeveloper here.