I recently came across a nice feature that Autodesk are providing for their users. It is now possible to have an interactive 3D viewer embedded in your site as shown below. Autodesk Design Review - QuickShare gives you the oppurtunity to upload your .DWF files and store them in the cloud to be viewed as a 3D interactive model. Unfortunately it is not yet possible to upload standard .RVT files, but it is of course possible to export your Revit models as a .DWF file.