Help and documentation: http://journeymap.info
Real-time mapping in game or in a web browser as you explore.
JourneyMap is a client+server mod for Forge which maps your Minecraft world in real-time as you explore. You can view the map in a web browser or in-game as a Minimap or full-screen. It comes in two editions: FairPlay (disables cave-mapping and radar in Multiplayer) and Unlimited (all features available in Multiplayer).
Check out http://journeymap.info/Server for information and configuration details.
Need to generate large map images?
Check out the JourneyMap Tools project.