In the past year, publishing 3D Objects has become a lot easier.
Silverlight can't do it yet. There have been promises but its soon to come.
When it comes to Flash - building a 3D object viewer is really very simple and its possible to produce a 3D object viewer within a few hours.
I'm aware of Papervision 3D. Of which you can simply drop a collada file into the viewer and it'll be displayed.
there are many other 3D engines built for flash. Alternativa3D, Away3D and Sandy to name a few. They all have their own strengths. Papervision is the general pick as it is been around the block and its at a level of which you can do pretty much anything you need.
Away3D is acclaimed for visual excellence and a prefab app that can assist in building 3D scenes
Alternativa3D has some beautiful examples and it has the ability to smooth render a scene whilst the camera is stationary.
Papervision3D - in my experience this is the fastest rendering engine. I've rendered speed of 60 fps with complex scenes. Its also the quickest on to set-up for view. Unfortunately at times it can be its own odd syntax and workarounds.
All these will assist you in your requirement.