Update 2011–12–14: It seems that a lot of people are coming here from web searches with phrases like “shapefile openlayers.” If all you want to do is display your data in OpenLayers, I’d highly recommend using a program like Quantum GIS to convert your Shapefile to a more web-friendly…

As you may have gathered, I like Git and GitHub. Today, I ran across a GitHub feature that is really cool and above and beyond the call of duty: not only do they produce and display diffs on text files, but also on image files! You can see an example in one of my repositories. Added points if you can figure out where the map tile is from!