Site : https://github.com/mazubieta/A-Star-Pathfinder
This is a demonstration tool using Python 2.6 and PyGame for the A* Pathfinding Algorithm.

After properly installing Python 2.6 and PyGame, to execute this demo:

$ python path.py

How to use it:

Cell Placement:

Place/Remove Start square       - CTRL + LEFT_CLICK
Place/Remove Goal square        - CTRL + RIGHT_CLICK
Place/Remove a Wall square      - SHIFT + LEFT_CLICK
		Note: 	You can hold this down and move the cursor to place several 	
				walls at a time
				
Reset Board:

Clear the entire board          - ESCAPE
Soft clear board                - BACKSPACE
		Note:	Leaves Start, Goal and Wall squares
		
Find Optimal Path:

Verbose Mode                    - ENTER
Instant	                        - RIGHT_ARROW
Step Through Path               - N

Change Heuristics:

"Straight Line Distance"        - SHIFT + 1
"Manhattan Distance"            - SHIFT + 2
"Zero" (Nothing Known)          - SHIFT + 3