Sandy is an intuitive and user-friendly 3D open-source library developed in Actionscript 2.0 and now Actionscript 3.0 for Adobe Flash.
PaperVision3D – Open Source realtime 3D engine for Flash
Away3D – Open Source realtime 3D engine for Flash
Kaon’s vSpace™ – From lightweight web 3D product tours, to stills and videos for Flash applications, extraordinary PowerPoint presentations, and now 3D PDFs, vSpace tools make interactive solutions possible for everyone.
Google Earth Extension for AutoCAD (publish your 3D models from AutoCAD directly into Google Earth)
Content creation programs which support Collada
Where to find Collada plugins: http://www.terathon.com/wiki/index.php?title=Collada_Plugins
SketchUp (you’ll have to unzip the .kmz file to find the .dae inside)
Photoshop CS3 Plugin
3D Studio Max
Swift3D (Flash only)