Today (15, Jun 2010) Microsoft announced that Office 2010 is available in retail so everyone can buy it, though Volume Licensing customers have been able to get their hands on it since April 27.
In this new version of Office Microsoft main goal has been to make it easier to store, edit and work with files online. With Microsoft Office Web Apps it is possible to keep versions of the same document synchronized so a whole group can work together on the same project, even though they are not at the same place.
As always Microsoft post a free beta version online, which you can download here:
http://office.microsoft.com/en-us/products/office-products-FX101825692.aspx