Samsung today announced that it has sold over 10 million units of its Galaxy S flagship smartphone since its debut in June.

The South Korean company, which hit the 5 million milestone in October, positioned the Android-powered Galaxy S as a challenger to the iPhone, launching it with nearly 100 carriers globally, including all four major U.S. operators — the Captivate for AT&T, Vibrant for T-Mobile, Epic 4G for Sprint and Fascinate for Verizon.

Google and Samsung recently teamed up to develop the Nexus S, the first smartphone to run on a new version of the Android. The Nexus S features near-field communication, or NFC, technology that lets people use the phone to pay for goods wirelessly.

Android is the second-largest mobile operating system worldwide, according to Gartner, only behind by Nokia’s struggling Symbian platform. In the U.S., Apple’s iOS holds a slight lead in market share, according to Nielsen.

Earlier today, Samsung said it plans to introduce the “Galaxy Player,” a digital media device that will take on Apple’s iPod Touch.