For those who haven't implemented A* before it can be quite an enlightening experience, and actually isn't too difficult once you dive in. It's a good introduction to priority queues too if you haven't played with them before.

I threw together an implentation of A* as a library in Go [1] for a game I've been doing, it has automated tests which mock up a game world and check the length of paths with visual output.

[1] https://github.com/beefsack/go-astar