I am running a forum-based RPG and we are using a jpg map, with the hurdle of having to draw on it using Paintbrush and then uploading it to the forum whenever the players want to move characters or troops. I started looking for collaborative drawing web apps or services and found Twiddla, wich is pretty nice, but I would need something to restrict players from viewing other players movements and having the Game Master be able to see everything. I may be asking too much, but may be you can help me with this :P
Also important: I saw what Roll20 is capable of doing, but it is mmuch to sophisticated and complicated. I am looking for something extremely easy to learn and use.