Based on latest market researches by Gartner and others it shows that still there are 2 main players in the mobile industry:
Android OS (Google) with ~56% market share, and iOS (Apple) with ~23% market share.
See the cut in the below picture:
The OEM market share cut, shows the following figures (Samsung and HTC leading the Android platform):
Not sure how many of you knows, but as of today there are around 4000 Android running devices by the various vendors (This number obviously is constantly growing):
We will need to see in the upcoming months, where does Microsoft Windows Phone OS fits in this puzzle with Nokia and Samsung starting to move forward with their mobile platforms and starting to gain some market share