How to use cycles stand alone with maya or 3ds Max
Write a render plugin for it.
As far as I know, the standalone is still a work in progress and is not exactly the highest priority at the moment (though it’s far enough along to render a wide array of scenes in).
Like J said, you will need to write a plugin for it if you want to use it with Maya.
And with the Cycles developer leaving to work on Arnold, the standalone Cycles development may slow down.
There is a Maya exporter forLux, however. A free render engine similar to Cycles.