2D Simulation tool for magnatics

Hi,
I was trying to understand phenomena of basic magmatic circuits eg. how the magmatic field looks inside a iron core when it is place in a uniform magmatic field etc.
I was looking for a 2D simulation tool in which I can simulate some of magmatic.
Maxwell, Magnets offers the trial version for a month but I am looking for a very basic freeware tool to use always in windows.
Please let me know if any one have an idea.

Regards,
Umesh

FEMM and QuickField are the best solution for your requirements