The first release was limited to a group of about 10,000 customers and partners, and the final product is slated for release in early 2007.
The beta is available as a download to the general public, but will expire on 31 January 2007.
Office 2007's most visible new feature is a user interface that will change according to the task that a user is performing.
The interface replaces current menus and toolbars with a 'ribbon' that will change according to the task. It aims to better advertise features that are available as part of the products.
"We think this is a great way to drive new productivity for users," said Kirk Koenigsbauer, general manager for Office Servers at Microsoft, during a presentation for press and analysts in San Francisco earlier this month.
"We are recognising that people aren't getting the full value out of the products. We want to do more with this results-oriented user interface to expose more of the functionality in the products that people can take advantage of."
Microsoft has also focused on increasing the suite's collaboration and integration features through Microsoft SharePoint and improved search capabilities for enterprises.
Individual applications offer a slew of feature enhancements. Word, for instance, will let bloggers publish posts directly from the application, and a new graphics engine for PowerPoint, dubbed Smart Art, provides templates and automatic layout tools.
The Outlook personal information management application has been expanded with a 'to do' bar that lists all upcoming tasks and appointments.
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