Highlight:
* MapTool allows you to 'host' your dungeon via the Internet (or your local LAN if you have lots of players who bring their own laptops) and while the DM has a sort of "God view" of the dungeon, the players can only see what the DM reveals (based on light sources or infravision or other senses.)
You can accomplish the same thing using GIMP, and if feedback warrants, an additional article can be written describing exactly how to use GIMP for gameplay.
A nice thing about Map Tool is it allows your players remote access over the Internet for groups who have players who can't be present. It even has a built-in chat utility.
* RP Tools also has a utility called Token Tool, which allows you to use any existing JPG or BMP file and convert it into a scaled token for use in MapTool. I've spent way too much time into the wee hours of the morning downloading various pictures and then converting them into tokens for my next game session. This is definitely one to look at.