know where i can get some good looking curtains..
reza, curtains are my biggest pain in the a**.
Well, we got few ways of doing them.
1 - very easy 
Find a good resolution photo of the curtain and map it on the plane.
then work the displacement map for it in photoshop and apply Vray Displacement.
2. Make’em with reactor as in this tutorial
Its translated from russian right in babelfish.