All our worlds except the current PVP map have DynMap live map renderer enabled. This means you can see what you are building in semi-real time through your web browser. You can also see what is going on around you, where you are in relation to spawn etc. The dynamic maps can be found at the following link:
The Creative world has what is called a 'Static' map. It is not updated real-time, however it is updated once an hour. It uses a plugin created by oliverw92 to generate the image then apply an overlay to it. This means it contains locations, names, cool pictures etc that help you navigate around the Creative world. Both the thumbnail-version and the full version are updated in real time. You can find the static map here: http://minecraftcc.com/creative.png - WARNING: ~20mb image file!
Creative, Build, Survival, and Lobby, each have a map rendered by Minecraft Overviewer.
The maps are updated every few months by RRiVEN when time allows. Each map takes 18+ hours to render and consumes 20GB of disk space.