As a refresh - since Blender 2.5 has a drastically faster raytracer, this concept of a rudimental indirect illumination can be rendered much faster than in the previous 2.4 version. However this still requires the Raytrace approach with Ambient Occlusion and thus is most applicable to simple 3D scenes if render time is concerned.
Everyone who's been in CG for a while has heard of HDR lighting, but sadly it is left to external renderers such as Lux Render or Yafaray. However I recently discovered that it is easily achievable in the Blender internal renderer, allowing anyone to create a brilliantly realistic render almost instantly! I simply couldn't keep this discovery to myself, so I decided to make a tutorial on it.http://blendernerd.com/hdr-lighting-tutorial/