Reposting my description from the luxrender forum:
In Lux, SSS is done in the following way:
You take a material that allows light to shine through it. This can be Null (completely transparent), Glass, Glossytranslucent or Mattetranslucent.
Then you take a volume with scattering support, most of the times you want the Homogeneous volume.
To control the scattered color, I would recommend to use the absorption color. So if you want that white light gets a red tint when scattered in the material, set the absorption color to red.
Remember to also set the absorption depth to the depth where the light should be completely red, e.g. 1 cm.
Leave the scattering color white and use the scattering scale to control the scattering strength.
I'll probably put this in the wiki when I find some time.