Map Making
There are ways to make maps, and there are ways to make maps.
Making Maps
There are a number of resources available to help you make maps right now and start using them.
By Hand
This is the only supported way to make maps right now. It is a tutorial that is created by the Map Master himself and hopefully maintained by him (with everyone's help). It is your first and best resource to what exactly goes into a map, how to put it there, and how it works in the game. Even if you choose to use a graphical map maker, you still need to read this, so consider it required reading.
These are features that are either in development or only available in a non-stable release. Use at your own risk!
Acme
Acme is a currently experimental mostly-doesn't-work graphical map editor that's in Armagetron Advanced's cvs. If you'd like to fool with it, go to this page and read about it, but be warned, it mostly doesn't work.
Viewing Maps
Nemostultae made a neat little web application that renders a map to a picture right in your browser. When used in conjunction with a text editor, it is a powerful tool to help make maps. In fact, the output of this page is currently considered required information if you want any server administrator to use your map on his server.