Algorithm for determining if 2 graphs are isomorphic

That's a quite difficult problem to solve. There is a Wikipedia page about it:

• Graph isomorphism problem

According to that page there are a number of special cases that have been solved with efficient polynomial time solutions, but the complexity of the optimal solution is still unknown.

My project - Griso - at sf.net: http://sourceforge.net/projects/griso/ with this description:
Griso is a graph isomorphism testing utility written in C++ and based on my own algo.
See Griso's sample input/output on this page: http://funkybee.narod.ru/graphs.htm