i dont know what a Head bumap is (i am blue belt so unoobed)
can u tell me
thx

A bump map is a texture that is used to obtain detailed 3D effects.
I am pretty sure someone here can give you a good example.
This example from Half-Life 2 is the best example I can give:

thx

You know, check out wiki.
They explain so much better than I do.

how to make bumpmapping?

well, you can download a plugin from this website: http://developer.nvidia.com/nvidia-t...dobe-photoshop for adobe photoshop. you can change the depth of the bump map with the "scale" setting. or you can download a plug in for gimp at this website: http://code.google.com/p/gimp-normalmap/