This tool is pretty decent and first and foremost, free. It can generate normal maps, displacement maps, ambient occlusion maps as well as some other ATI specific stuff. It's easier to use than blender or any other 3D app that can bake, especially when you don't model in them.
It can import Wavefront OBJs and two other formats unknown to me. Good for wings3d users, it does not mess up anything upon importing. Just make sure you don't have any unmapped faces on the low res mesh. The high res mesh doesn't need UV coords.
The results are quite nice for anything without consistent mirrored UVs (see the seam at the back of the head for example, quite ugly).
You might have to save the generated maps from within the application in a different format as it generates them as 32.32.32.32 DDS.

