I've been working with Reaction-Difusion systems recently and built a library to facilitate simulation of such systems. The library is aimed at 3-dimensional Reaction-Diffusion, multi-threaded and released under the BSD License. An example is included which you can also run out of the box.

More info at Volatile Prototypes.

Thanks,

Yiannis

Yiannis Chatzikonstantinou
http://volatileprototypes.com
http://yconst.com