As far as I can find, there is no babel support for Mathematica. So I wrote one and share it in case other people are interested:

https://github.com/tririver/wy-els/blob/master/ob-mathematica.el

It is also discussed in this blog http://cosmosimple.blogspot.co.uk/2014/01/evaluate-mathematica-code-in-emacs-org.html 

While writing this extension, I have a question: How to add font-lock mode in org code blocks? I had a read of ob-C and ob-python code and didn't find out how they do font-lock.

Note that the font lock support for Mathematica is available as mma-mode at

https://github.com/skaslev/emacs.d/blob/master/progmodes/mma.el

For my case in a .m file I have font lock from mma.el, but not src code blocks.

Best wishes,

Yi