I don't know if this is the right forum. A bunch of people in that One Question thread said that D&D was their guilty pleasure.
I played D&D for the first time last Saturday, and it was done entirely online. We did it via http://rptools.net/doku.php. I'm not the GM, but I think he basically had to scan in the maps he wanted to use, and create the tokens that each character wanted to use. Dice rolls are done entirely in chat (visible to everyone). There are a bunch of more options you can choose to use, but they're not required.
Just wanted to let everyone who plays know about it (and if someone on here wanted to GM, I'd gladly play a second adventure ;-)).