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 stopped working on Unfolder after Blender 2.5 came out as I didn't have the time to convert it to the new API. Maybe one day I'll write a new one, but there are other unfolders out there and you can always use Unfolder with Blender 2.49
acknowledgements
post at (ignore this text) celeriac dot net