Awesome Automated Z-Depth Shader Mel Script...and it is FREE :)

Z Depth in Maya using Mental Ray can be a pain in the ass, but recently I found this script that automatically creates custom Z Depth Shaders for you. Perhaps the coolest thing is that it preserves the transparency of any alpha channel your textures might have. A HUGE time saver. You can find the Z-Depth Mel script at the links below along with many others:
http://boscripts.blogspot.com/2010/02/z-depth-with-maya-and-nuke.html

http://www.bohdon.com/scripts/

Check out a tutorial here:
http://www.bohdon.com/access/blogFiles/boScripts/boZDepthShader/zDepthTutorial.mov