In case you haven't heard, beta 2 of the 2007 Microsoft Office System is available on the Microsoft website.
You can try out the new versions of old standby Office applications like Word, Excel, PowerPoint, and Outlook. You can also try out the new Microsoft Office SharePoint Server (MOSS) 2007 suite, which includes SharePoint, Enterprise and Web Content Management (ECM/WCM), Forms Server, and Project Server.
Download the beta. Set up a virtual machine or two. Install the client and server applications. See how they work together. Send Microsoft your feedback.
And the best part, it's all free to try during the beta!