This is amazing! It's an interactive map of Springfield that a fan put together. Click anywhere on the map to zoom in - the black text represents retail stores and the pink text represents restaurants. If you hover your mouse over the green boxes, you can view a screen cap of that particular building.
I can't imagine the time it must have taken to put this together! Even if you don't care that much about the map itself, it's worth it just to go through and read the clever names of some of the establishments - the Texas Cheesecake Depository cracks me up.
Link via Instructables.