Gonna need a map editor

So I've been thinking about Pac-Man mazes--how to build them, how the ghost AI will navigate them, etc.--and I've come to the conclusion that I'm going to need to write a level editor in which I can construct a graph (I think) of the maze, with nodes at the intersections. Each node would have a link to neighboring nodes, with distance and direction information.

Problem is, I'm not written a level editor before. Or worked with graphs before. So I guess I need to go do some research.

There might not be screenshots for a while.