I said Autodesk Freewheel twice for a reason as there are now two locations and versions for viewing DWF files with no install of viewer software. There is a released version and an Autodesk Labs Technology Preview version and both are FREE.
What is Autodesk Freewheel?
In developer speak:
In simple terms it allows you to view 2D and 3D DWF files on the web in your browser without installing anything at all on the local machine and platform independent as long as your browser supports Java. Upload, Share, View, and Print 2D and 3D rich design data with no hassle.
The released version of Autodesk Freewheel is located at: http://freewheel.autodesk.com/
The Autodesk Freewheel Technical Preview version that will evolve and may contain features that are being worked on for possible future versions is located at http://www.dwf.com and also mentioned on Autodesk Labs.
More on the two flavors and why at: http://labs.autodesk.com/technologies/freewheel/documentation/
Want to know something cool? The raster images in this blog post is also a DWF, I mean still is a DWF rendered as an image by Autodesk Freewheel click on them. Learn more at http://freewheel.autodesk.com/developers.aspx.
I also posted a Highlights Page of Freewheel examples on the right side menu of this blog Autodesk Freewheel Examples.