Obsidian Portal. RPGtonight Free Online Virtual Tabletop for Role Playing Games. MapTool. The jewel in the RPTools crown, don't let the name fool you.
MapTool is much more than just a mapping program. Included are not only powerful tools for the creation of detailed maps, but also a chat function, detailed token management (allowing you to track properties of the units placed on the map and display health and status information), and an initiative tracker. Roll20: Web-based online virtual tabletop for all roleplaying games (RPGs)