The official site/store for "Land of Og", a funny role-playing game with an interesting mechanic: players may only communicate with a small vocabulary of 'caveman' words.
Pretty interesting attempt to preserve the best aspects of pen and paper rpgs within a software interface. Haven't personally tried it out, but it looks promising.
This page covers various attempts to describe RPGs in general terms. Rather than telling you how to roleplay, this is a collection of articles on what the different ways are -- and the pros and cons of different choices.
Free software for simulating tabletop RPGs online. Great for gamers who are unable to gather with others on a regular basis due to time or distance constraints.