Hi,
Some time ago I was programming path finding engine and there is source:
You can check how it looks and works here: http://www.shadowsgames.net/tests/pathFinder.swf
You can use This engine in your game, nice if you will add me in credits :). All is on 2D arrays, I created few useful functions in gridManagers. Maybe someone will help this project to speed up searching ;).
Hope it will help!