texture mapping?

I wanted to know how to map a polygonal mesh surface and bring it into the gimp so that I can paint it.
I had seen this done with maya before and I wanted to learn how to do it in blender. Thanks for any help!

Unwrap your model using ( with UV face select mode) the uv image editor and set out all faces in the layout you want. Then gotto the scripts window and run ‘Save UV face layout’.