As recently as a year ago, many enterprises couldn't have imagined that the iPhone would now be second place in terms of security features that enterprises require, behind only the BlackBerry and ahead of Android and Microsoft's Windows Phone 7.

But at the end of 2010, that's how many enterprises regard the smartphone landscape. Over the next couple of years, experts predict that BlackBerry will hold onto the most security-conscious enterprises but that the other platforms will take up a growing share of the market.

The release of iOS4, the latest iPhone software that came out in June, marked a dramatic shift in the enterprise smartphone market. With that update, many CIOs grudgingly admitted that the iPhone had became "good enough" to meet the most basic security requirements that most enterprises need, said Tim Weingarten, CEO of Visage Mobile.

Visage Mobile's software manages 100,000 devices from US corporations of every size. Among those devices, BlackBerrys still outnumber iPhones and Android phones 10 to one, he said.

Research In Motion currently has 51.2 percent market share in the enterprise, according to recent research from comScore. Apple follows with 22.7 percent and Android comes in third with 12.1 percent market share. Microsoft trails at 8.8 percent, comScore found.

In the wider market, RIM's share of the USmartphones in the enterprise: A changing landscapeS smartphone market dropped from 39.3 percent in July 2010 to 35.8 percent in October 2010, ComScore said.

The smartphone mix in an enterprise often depends on who actually buys the phones. Corporations that decide to standardize on a platform and issue phones to workers tend to go with BlackBerry, said Tony Kueh, senior director of enterprise mobility management for Sybase.

But when companies offer to subsidize the users' data plans and let workers buy their own phones, people are choosing iPhones, he said.

Updates to the iPhone since it first launched have allowed it to be an option for corporate workers.

"If you'd talked to someone in IT at a typical corporation prior to the launch of iOS 4, they would have said it was nowhere good enough and they weren't going to support it," Weingarten said. But there was "a sea change with iOS 4," he said.

Now the iPhone offers just enough security to make it palatable to most enterprises, he said. Onboard device encryption is built into the hardware and it supports remote wipe and kill as well as passwords. The iPhone supports 20 of about 40 policies built into ActiveSync, he said.

Android has improved with version 2.2 of the software, but most enterprises say it isn't there yet. "Android is a few steps behind the iPhone in terms of security capabilities," Kueh said.

Google has just released Android 2.3, which will first become available this week on the Nexus S phone. "I did not see any feature enhancements for enterprises in 2.3," said Ken Dulaney, an analyst at Gartner. "I suspect and hope there will be announcements for the enterprise in 3.0 because right now the Android system is about where iPhone 2 was."