Unfolder unfolds meshes into SVG nets automatically, with optional manual guidance. Unfolder can also generate distortion-free UV maps and animate unfolding of meshes.

Unfolder is distributed with Blender (mesh>unfold)

I am working on the next version now. It should be ready for Blender 2.5.

• Unfolder 3.0beta
  latest untested development version
  put it in your .blender/scripts folder
• polyhedra.zip
  zipped .blend file of some nice polyhedra