Sketchfab.com just added a material editor to their webgl models.. this video shows you how to enable it on older uploads. newer uploads will have it enabled by default.
These are the settings you can manipulate:
(note: your model obviously needs to be UV Unwrapped for the textures to work)
Diffuse Color – You can use the original diffuse texture if you uploaded one with your model, or use the color picker to re-color it.
heres my old one
and the new
Lightmap – for pre-baked lighting on your models.
Specular Color – This controls the intensity of the texture/color meant to reflect in light.
Shininess – This slot controls the sharpness of the specular map, and higher settings make the material glossier.
Normal Map– works best with an actual normal map.
Opacity – Controls any transparancy in your materials, or model selected.
Emission – This controls any part of your model you would like to have a glow or self-illumination.
Environment Reflection – This setting is used only if you enabled a cubemap as environment..and is multiplied by the specular color.
the model above can be viewed at http://skfb.ly/l4hgfe1da