How to implement A* to have an AI trying to reach the player

Hello, I need to implement A* so that enemies try to reach the current player's position, by avoiding obstacles. So that every few frames, the enemy calculate the best way to reach its destination and try to do it.

My question is, what is the best and most simple technique to do it? Is placing a nodes grid on the level any good? I read about rays to detect obstacles but thats all I know.

Thanks in advance!

Download Path from angry ant http://angryant.com/

There are some things that need fixing before it'll work with Unity 2.6

Mr. Joy's version has a handy DLL which I've used previously to great effect:

http://github.com/MrJoy/Path-GPL

Version 1.1 will come out with Unity 3 support after Unity 3 is out.

Another A* program:

http://www.arongranberg.com/unity/a-pathfinding/

I've created a barebones textbook implementation of the A* method and added it to the wiki. http://www.unifycommunity.com/wiki/index.php?title=AStarHelper