Thanks to Josh at Windows Connected for pointing out a new download now available that adds in menu options to be able to open and save documents directly to Office Live Workspaces when it becomes available.  From the download details:

The Office Live Add-in will install new menu options in Microsoft Office 2007 and a toolbar in Microsoft Office XP and Microsoft Office 2003. You will be able to open documents located in Office Live Workspace directly from Microsoft Office Word, Office Excel, and Office PowerPoint. You will also be able to save files directly from Microsoft Office Word, Office Excel, and Office PowerPoint to your Microsoft Office Live Workspace.
You can pre-register for Microsoft Office Live Workspace at http://workspace.officelive.com.

Pre registration requires providing a phone number for a verification sequence, a simple process.

Office 2003 Add-In (toolbar)

Office 2007 Add-In (menu option)

According to the initial announcement of Office Live Workspaces, which will provide 500mb of free storage "in the cloud", the beta is set to begin "in December".  We would expect that to be early in December, based on the appearance of this add-in, and the crush of the holidays coming later in the month.  We'll keep you posted, but you can subscribe to the Office Live Workspaces blog for updates as they become available.