Today, there are two versions of Android: one for tablets and one for smartphones. Android chief Andy Rubin said Google "took a shortcut" by not making Honeycomb available for phones, or under an license, because Google didn't want manufacturers to "wedge" a tablet OS onto phones.

But Ice Cream Sandwich, to be available by the end of 2011, will represent the "re-merging" of the tablet and smartphone versions of Android and be fully open source, Rubin said in a briefing with reporters.

"Ice Cream Sandwich will be the next big open source release toward the end of the year," Rubin said. Applications built today can run on both smartphones and tablets, but Google said Ice Cream Sandwich will make it easier for developers to build applications optimized for both.

Google is also partnering with most of the major carriers and device manufacturers to guarantee that new Android devices will receive the last software updates for 18 months after launch, as long as the hardware is capable of running the latest versions of Android. Until now, there have been long delays in carriers rolling out updates to users. For example, just have been upgraded to Android 2.3, the latest smartphone version. The partnership behind the 18-month guarantee includes Verizon, HTC, Samsung, Sprint, Sony Ericsson, LG, T-Mobile, Vodafone, Motorola and AT&T.

Although version "fragmentation" hasn't hampered Android's growth, Google said it's in the best interests of developers to be able to develop for a single version of the operating system. Android does not provide a consistent experience across devices the way Apple does with iPhones and iPads, but this is a step in that direction.