Unwrapping sculpted head with multires

So I have sculpting my first head in blender hooray (I attached a pic if anyone cares to see)! However, now I want to unwrap it and am a little confused how to do that considering I am using a multires modifier. Do I unwrap the base mesh or a higher level? Do I need to apply it before I unwrap? Can anyone help me out?

Thanks a bunch,


Here is good tutorial.

Great thats exactly what I was looking for! thanks a lot!