Walt Disney Co. has acquired iPhone game developer Tapulous, extending the entertainment company's push into mobile games.

Tapulous founders Bart Decrem and Andrew Lacy and their development team would join Disney's Interactive Media Group, Decrem said on the company's blog Thursday. Financial details were not disclosed.

Founded about two years ago, Tapulous is best-known for the game "Tap Tap Revenge," one of the most popular offered through Apple's App Store. Tapulous claims the game has been downloaded more than 35 million times and played more than a billion times.

At Disney, Decrem said he and his team would continue to develop games focused on music, "but we'll also push into new and exciting areas of mobile social entertainment."

Tapulous investors include Marc Benioff, chief executive of Salesforce.com, and venture capital firm Khosla Ventures. As of December, Tapulous sales came close to $1 million a month, according to the Reuters news agency.

The popularity of the iPhone and other smartphones has provided a huge boost to the mobile gaming market. Games are the most popular downloads from mobile application stores provided by handset makers. Revenue from such online stores is expected to reach $6.8 billion worldwide this year, compared to $4.2 billion last year.

Apple has the largest application store, which has driven the success of the iPhone. However, competition is heating up, particularly from Google. The search engine launched in October 2008 the Android Market for applications that run on smartphones built around Google's Android operating system. Multiple manufacturers make Android-based phones, which are growing in popularity and present a significant challenge to Apple and Research In Motion, maker of the BlackBerry smartphone.