RPTools is a brand of open-source programs designed to enhance traditional pen-and-paper role playing games. They can be used for face-to-face play, or Internet role-playing in real time even if your players are on the other side of the world. MapTool (which is our free virtual tabletop application) in particular works great with voice-chat services!
These tools are not a role playing game by themselves, nor are they meant to replace everything at the RPG table. Rather, they are designed to be as flexible as we can make them, usable for a wide variety of gaming systems, from fantasy to sci-fi; from tabletop miniatures games to purely spoken-word games.
The tools aren't built from the ground up for any specific RPG, which is what allows for the great flexibility we have, but as a result, it can be difficult for us to indicate easily to individuals how best to make use of the tools for their specific purposes. Fortunately, the community forums are a thriving, active source of rapid responses to any questions you may have. We take pride in this as one of our greatest strengths and we encourage you to join us there. If the game you want to run is a commonly-found one, there's a good chance you can locate someone who's done most of the fine-tuning for you! At the risk of leaving some out, our users have developed frameworks for D&D3.x, D&D4e, Pathfinder, ShadowRun, nWOD, GURPS, and many others.