Microsoft is set to broaden its battle with Google this week as it pushes ahead with online versions of some of its core software, including final plans for a “cloud” operating system designed to extend Windows to the internet. The news comes days after Google took aim at Microsoft with the announcement of a PC operating system of its own, dubbed Chrome OS.

The rival moves point to an intensification of the battle between the technology giants, with Google trying to extend its internet platform to PCs, and Microsoft moving in the opposite direction. While Google’s PC operating system is not due to appear in new computers until the second half of 2010, Microsoft’s cloud operating system will be launched formally this year.