Mobile phone sales in the U.S. reached 33 million units in the second quarter of 2007, according to the NPD Group.

That is close to a 17 percent decrease compared to the first quarter of 2007. NPD says the second quarter is usually slower for mobile phone retailers.

"Despite seasonal slowness, the industry showed healthy year-over-year unit and revenue increases," Ross Rubin, director of industry analysis for NPD, said. "Consumers are seeing value in moving to handsets that offer data-driving capabilities."

The good news for mobile phone retailers is that NPD estimated total second quarter 2007 consumer sales hit $2.4 billion, up 14 over the same period in 2006.

Carrier stores accounted for 62 percent of sales in the second quarter of 2007. Mass merchandisers and department stores took in 9 percent of sales, and electronics specialty stores had another 5 percent of sales.

Mobile Phones