Research firm NPD today announced the release of its new Mobile Phone Track report for the second quarter of 2011, showing Android continuing to lead the U.S. smartphone market with 52% of new sales during the quarter. Apple's iPhone checked in with 29% of the market while Research in Motion's BlackBerry devices continued their free fall and garnered only 11% of the market.



SplatF pulls out one key detail from the full report, noting that not only is Apple's 14-month-old iPhone 4 continuing to lead the market in sales, but that the 8 GB iPhone 3GS takes the second spot in the rankings. The iPhone 3GS was introduced 26 months ago, and Apple kept the device around following last year's iPhone 4 introduction by dropping the capacity to 8 GB and offering it at a $99 price point for entry-level users. Pricing has since dropped to $49, with occasional deals bringing the price as low as free.

Here are the top five best-selling phones during Q2, via NPD’s Mobile Phone Track service: 1. Apple iPhone 4

2. Apple iPhone 3GS

3. HTC EVO 4G

4. HTC Inspire 4G

5. Samsung INTENSITYII



Apple has attempted to keep sales momentum for the iPhone 4 moving forward with the introduction of a CDMA version on Verizon and the much-delayed launch of a white version of the device earlier this year. But even as Apple has diverged from its usual annual cycle of iPhone releases by pushing the iPhone 5 out to September or October this year, the iPhone 4 and even the iPhone 3GS continue to top the charts in U.S. sales.