Mobile-phone sales reached 314.7 million units in the fourth quarter, down 4.6 percent from the same quarter a year earlier, Gartner said on Monday. The phone market did expand for the full year, however, growing 6 percent compared to 2007.

Despite the reluctance of end-users to buy new phones, when they do make a purchase they are more frequently opting for a smartphone, said In-Stat. Researchers there predict that by 2013, smartphones will double their share of all cell phones worldwide to about 20 percent.

Gartner found that North America has already reached that level. New products like Research In Motion's Storm and the Android G1 helped smartphone sales account for roughly 20 percent of sales in the region, Gartner said.

People are drawn to smartphones because of the ability to download new applications, In-Stat said.

The slower growth is creating an opportunity for new entrants in the smartphone market. In-Stat believes that smartphones with the Linux operating system will see the most growth, though they will be second-best in volume behind Symbian. That means Linux will outpace Windows Mobile, RIM and the iPhone, In-Stat said.