There is a new Autodesk 360 Viewer "A360."  The new drag & drop web based viewer allows you to view and share designs without any install, sign ups, or plugins and over 50 2D and 3D file types are supported.

Check out the new viewer! http://360.autodesk.com/viewer

Read here for a blog post from the A360 Team which shows more of the features that will be added in the future currently being worked on in the lab.