I really hope there will be some way, either directly or by an automatic converter, to use the simple greyscale bump maps
Your in luck (if you use Photoshop). NVIDIA has a free downloadable Photoshop plugin that converts greyscale bump map images into normal maps. At the bottom of the list:
http://developer.nvidia.com/object/nv_texture_tools.html
Im sure most higher end 3D applications output normal mapping. I use Lightwave and it does. Here are some video tuts:
http://www.simplylightwave.com/movie_pages/tutorial.mhtml?tut_id=517
Also, a lower cost app I like called ZBrush is beta testing normal mapping output for its next update. Check out the cool screenshots here:
http://www.pixolator.com/zbc-bin/ultimatebb.cgi?ubb=get_topic&f=1&t=011757
More ZBrush:
http://www.pixolator.com/zbc-bin/ultimatebb.cgi?ubb=get_topic&f=1&t=012018