Google unveiled Android 3.0, known as Honeycomb, earlier this year, billing it as the first version of its Android operating system designed from the ground up for use in tablet PCs. Honeycomb software is already available on the Motorola Mobility Inc Xoom tablet, which went on sale in February.

The software represents Google's first dedicated effort to challenge the dominance of Apple Inc's iPad in the nascent tablet PC market.

But Google said it will not immediately make its Honeycomb software available as open source code, the company's traditional practice with Android whereby any developers are free to modify the software as they see fit. The reason for the delay, Google said, was because Honeycomb was not ready to be customized for use on smartphones.

More: http://www.reuters.com/article/2011/03/24/us-google-idUSTRE72N8E620110324