iPhone market share grew 327.5%

We've known since October, when Apple released its latest earnings report, that the iPhone had a bang-out summer - shipping nearly 7 million units in the quarter, up from just over 1.1 million the year before.

But it wasn't until Thursday, when Gartner Research issued its smartphone sales report for the third quarter of 2008, that we learned just how well the iPhone did vis-a-vis its competitors.

Apple's (AAPL) share of the worldwide smartphone market leaped 327.5% in Gartner's survey, catapulting past Microsoft's (MSFT) Windows Mobile to grab the No. 3 position and putting it within striking distance of Research in Motion's (RIMM) BlackBerry for the No. 2 spot.

Smartphones running on Nokia's (NOK) Symbian operating system are still No. 1, with nearly 50% market share, but they lost ground as Symbian sales shrank for the first time, down 12% for the quarter.

Apple's results would have been even more impressive - and would have knocked RIM off the No. 2 perch, as Steve Jobs claims -  if Gartner's researchers hadn't reduced the iPhone's quarterly sales numbers by the more than 2 million units that Apple shipped before the end of the quarter but were still sitting in inventory.

Gartner's preliminary sales figures - listed both by vendor and by operating system - are available in its press release here.  But they are easier to visualize in the bar graphs, pasted below the fold, that Ars Technica's David Chartier has helpfully produced. See here.