Where i can downlaod free 3d models for games?

I would suggest 3D Cafe. They have a very large selection of free stuff. Most of it is pretty low detail though (you have to pay for the good quality stuff). I suggest only using the models from there as "place-holders" while developing your engine and then make your own later. Link follows.

http://www.3dcafe.com/asp/freestuff.asp