The following videos Motion Vectors out of Maya is a set of 4 tutorials prepared by Arkadiy Demchenko.

Many of RE:Vision Effects tools support motion vectors inputs including: ReelSmart Motion Blur, SmoothKit Directional, RE:Map Displace, Video Gogh, Twixtor Motion Vectors In.

This process will be useful to RE:Vision Effects users in Shake, Maya and Max Composite, Nuke, Fusion, After Effects, Combustion and others.

01_Basics I. This video explains how to install a special shader to
render motion vectors with Mental Ray.

02_Basics II. In this tutorial we review some theory on how to render motion vectors properly and show a couple of tricks and things to keep an eye on. The tutorials are done in Maya 2009 but will apply to

03_Example I. Simple example scene with an animated spider. Using lm2DMV shader as well as Maya 2009+ passes system to get motion vectors.

04_Example II. Another example scene with a tower blowing up into pieces. Only Maya 2009+ passes system is used in this example.

A set of Maya scene project files to test the content of this tutorial by yourself and compare your results is maintained here:

http://www.revisionfx.com/support/faq...
The 2009 scenes can be uploaded directly in 2011 without issues.

P.S. Keep in mind that Sun&Sky system used in this scene creates a gamma correction lens shader for your camera that needs to be disabled / disconnected if you want to render the scene with lm2DMV shader. Passes on the other hand will ignore it, so no need to bother then.

Arkadiy maintains the blog http://www.sigillarium.com about Maya and his work.