Wireless customers downloaded 7.9 billion apps in 2010, with Apple still leading the way, according to a report released today by ABI Research.

According to ABI’s estimates, the iPhone interface had notched up more than 5.6 billion accumulated downloads by the end of 2010, compared to nearly 7.9 billion total downloads from all stores during that year. However, Apple is set to face more intensive competition in 2011.

“The iTunes App Store only targets iOS users; that leaves more room for other platform application stores to step up and focus on ‘non-Apple’ clientele,” said research associate Fei Feng Seet in a press release.

Android smartphone quarterly shipments now exceed Apple’s. There is still a long way to go, but accumulated downloads from both Android Market and third-party platforms surpassed 1.9 billion by the end of 2010. Android Market currently features more than 130,000 apps in 48 countries, nearly half of iTunes App Store’s catalog.

Seet notes that Research In Motion (RIM) has been making a conscious effort to increase BlackBerry’s footprint in the mobile apps market, as seen in its recent aggressive expansion to over 100 markets and developer conferences it has held in United States and Indonesia.

ABI Research estimates that accumulated BlackBerry app downloads totaled more than 1 billion as of December 2010.

ABI’s mobile marketing practice director, Neil Strother, notes that network operators are also considering entry into the mobile application market. “India’s Idea Cellular, for example, just launched its Online Application Store shortly in advance of its 3G network launch,” Strother said, adding that multi-platform-supported app store GetJar has just raised $25 million for further expansion and plans to secure its position as the premier open-source app store.