More normal mapping

The grayscale maps are generally bump maps, so yes, tangent space maps. Normal maps (the 'colorful' ones) are relative to the object I think.

Here's a photoshop plugin to convert hightmaps to normalmaps - http://developer.nvidia.com/object/nv_texture_tools.html

I coulda sworn this used to be a commandline tool from nvidia but oh well. You'll need somthing more complicated if you want to convert a bumpmapped model to a normal mapped one.