The latest report from market research firm Gartner suggests that mobile apps are big business, and that business should only grow in the next few years. According to Gartner's numbers, Apple completely owns this market, grabbing almost every one of the 4.2 billion dollars spent on mobile apps in 2009. Based on Gartner's estimates and our own analysis, Apple could hold on to at least two-thirds of the market if current sales trends hold for 2010.

Apple first opened the App Store in July 2008, along with the launch of the iPhone 3G and the release of iPhone OS 2.0. Sales were brisk, with 300 million apps sold by December. After the holidays, that number had jumped to 500 million. Earlier this month, Apple announced that sales had topped 3 billion; that means iPhone users downloaded 2.5 billion apps in 2009 alone. Gartner's figures show another 16 million apps that could come from other platform's recently opened app stores, giving Apple at least 99.4 percent of all mobile apps sold for the year.

"As smartphones grow in popularity and application stores become the focus for several players in the value chain, more consumers will experiment with application downloads," Stephanie Baghdassarian, research director at Gartner, said in a statement. "Games remain the number one application, and mobile shopping, social networking, utilities and productivity tools continue to grow and attract increasing amounts of money."

Gartner's predictions for 2010 are 4.5 billion apps sold, for a total of $6.8 billion in revenue. If Apple can merely maintain its current rate of about a quarter billion app sales per month, it stands to be responsible for 3 billion apps sales—67 percent—good for $4.5 billion in revenue. Apple's cut would be $1.35 billion, with developers taking the remainder. However, as Apple gains more users from sales of new iPhone models and possibly froman expected tablet, Apple could get an even larger share of the mobile app market.