John Morgan's Story of Zoo Keeper page. This page contains information about the creation of the arcade game ZooKeeper. Claimed by many to be one of the finest arcade games. This page contains a wealth of information about Pacman and Pengo hardware programming. Many of the documents also contain material that apply to arcade game development in general.
Source is also available, and contains a lot of information about the system.
OpentUME is a very flexible map editor. It was initially used to create commercial games for the SNES and Genesis. The AS MacroAssembler . Support 6809 cpu among others. This is the assembler needed to compile the Incredible Technologies demo.