According to October 2010 data from The Nielsen Company, 29.7 percent of U.S. mobile subscribers now own smartphones that run full operating systems.

The most popular smartphones are the Apple iPhone and RIM Blackberry, which are caught in a statistical dead heat with 27 percent of smartphone market share in the U.S. Twenty-two percent of smartphone owners have devices with the Android operating system.

When mobile users who planned to upgrade to a smartphone in the next year were asked about their next phone, Apple's iOS and Android were tied for "most desired" operating system, Nielsen found.

Among users planning to get a new smartphone, current smartphone owners showed a preference for the Apple iPhone (35 percent), while 28 percent of both smartphone and featurephone planned smartphone upgraders indicated they wanted a device with an Android operating system as their next mobile phone.

Featurephone owners planning to get a smartphone are less likely to have made up their mind about the OS they will choose: 25 percent were "not sure" what their next desired OS might be compared to 13 percent of smartphone owners. Those over 55 were markedly less certain than younger mobile users, with 27.8 saying they weren't sure what kind of device they wanted next, compared to 12.2 percent of those 18 to 24.

Apple's iPhone and devices with the Android operating system were the "most desired" among likely smartphone upgraders, with Apple showing a slight lead among those age 55+ , 18 to 24, and 25 to 34

. Women planning to get a smartphone are more likely to want an iPhone as their next device, with slightly more males preferring Android, according to Nielsen's data.