iPhone is on fire! In just matter of a year, iPhone has nearly double it's unit of sales worldwide.  Looking at smartphone OS market share alone, Gartner shows the iPhone OS, Android, and RIM making the biggest gains (up 6.2, 3.4, and 3.3 percentage points from 2008, respectively) at the expense of Windows Mobile (off 3.1 percentage points) and Symbian (off 5.5 points).

Gartner estimates 172 million smartphones were sold last year, up 24 percent. In contrast, total mobile phone sales were flat at 1.2 billion. Smartphones represented 14 percent of total mobile handset sales last year, up from 11 percent in 2008.

source: mobilecrunch