Microsoft as today cut the ribbon on the official release of its cloud-based productivity suite, Office 365.

Aimed at businesses rather than individuals, the service comprises Exchange Online (for email and calendars), SharePoint Online (for online collaboration), Lync Online (for text, audio and video messaging and conferencing), plus browser-based versions of Microsoft Excel, Word, and PowerPoint in addition to the traditional installed versions.

Priced between $2 and $27 per user per month, Microsoft is targeting enterprise customers, small businesses and the education market with Office 365. Microsoft is promising updates to the service every 90 days.

Microsoft’s clear rival here, of course, is Google. Office 365’s Digital Marketing Lead for Office365 just cheekily tweeted “Interesting…Serving up lots of site requests for Office365.com from certain IP range in Mtn. View,” suggesting that Google is keen to check out the official, out-of-beta version of the service. However, as our own Microsoft specialist Alex Wilhelm recently noted, Google Docs is still some way ahead of the cloud-based Office suite in terms of functionality.

Screen shot 2011 06 28 at 15.33.16 Microsoft officially launches cloud based Office 365