Juan Pablo Bouza has released BlenRig 4.0 – Auto Rigging & Skinning for Blender 2.57b. BlenRig is an automatic rigging system that uses an armature and a mesh deform cage to produce a ready to use rig with nice deformations and a wealth of animator friendly controls.
You can download this addon here: Download
Tutorials you can fin here: Tutorials
Source and full article: Blendernation