previous RPG posts). Usually these encounters take place a confined area (a room, a forest clearing, etc) so there is no problem in setting out the scene on the table top. Similarly mapped areas have interconnecting tunnels, roads, paths, etc between key areas, making them easy to jot down and expand on.
My groups next session sees them (hopefully) assault the Castle Wittgenstein in the Warhammer Fantasy "Enemy Within" campaign. Now this is a large courtyard centred map with lots of differents areas within to explore and fight in. There is no way I can use my usual methods of mapping to unveil/describe sections whilst keeping others hidden and still give my players a good idea of the layout of their surroundings. So I've decided to turn to electronic means. Now, I personally don't like using computers to help play my paper & pencil (and lead) RPGs. I find that they usually cause the game to pause whilst the GM clicks on the relative link or file, breaking the flow of action and distracting the players.
Anyway I'm going to display to the players a map of the castle with the areas they haven't seen greyed out, then rub out the grey as the areas come into view. I'll attach a screen to my laptop to face the players so that they get a better view of what I'm doing and I don't have to put my neck out of joint craning round to see the screen. Its not rocket science.
To set up the "Fog of War" I will be using the free graphics package GIMP which is pretty powerful, free and multiplatform. Please note that I'm going to assume some knowledge of graphics packages here. All the tools and techniques used here are basic. Gygax knows, I'm no graphical artist!