A report from Nielsen shows that in the smartphone market, it's a battle between Android and iPhone for many users, with Blackberry holding its own but in danger of losing its traditional dominance.

A survey of more than 19,000 mobile subscribers, conducted by the Nielsen Company, showed 29.7 percent of them had a smartphone with a full OS.

Of the smartphones, the most popular operating systems were the iPhone and the Blackberry, followed by Android. The iPhone captured 27.9 percent of the market, followed by the Blackberry at 27.4 percent and Android at 22.7 percent.  

The company that makes Blackberrys, Research in Motion, said it had lost market share in January of this year. But it isn't clear whether that loss is a function of more people using smartphones away from corporate settings, rather than fewer people using Blackberrys. Blackberrys have always been strong among business users, but they are a smaller share of the total smartphone market than previously.

Blackberrys were weaker, however, when users were asked about the next phone OS they planned to buy. Thirty percent said the iPhone, putting it ahead of both Android (26 percent) and Blackberry (13 percent).

The difference was even more marked when respondents were divided up by age. Thirty-five percent of those aged 18-24 said they planned to buy iPhones, and 32 percent said they were planning to upgrade to Android-based models. Blackberrys were a distant third, at 11 percent.

The two demographics that showed iPhones in second place were those that own featurephones already and men. Men were more likely than women to want the Android OS, with 32 percent saying that would be their next smartphone versus 22 percent of women. Featurephone owners also preferred Android, with 28 percent saying they planned to upgrade to that OS over 25 percent that said they planned on buying an iPhone.