I've been reading up a little this morning on Microsoft's new online productivity suite for businesses, called Office 365. It's fair to think of it as the next generation of BPOS. Basically, it's a mix of on-premises and cloud software. You get Office Pro Plus on your desktop, and Exchange Online, SharePoint Online, and Lync Online (for communicating and hosting meetings) in the cloud. Office 365 is currently in beta, but it's slated to be available for purchase in 2011. There is a nice list of top questions on the Office 365 blog.
Personally, I like that Microsoft has made this a really great option for small businesses, by providing the service to them for $6 per user per month. Nice move there.