I have been using internet message boards (like enworld.org or boards1.wizards.com/gleemax) and an online die roller database (www.nadaka.us/DiceBoxDB.asp) for some time. However it can be slow going at times with each round of combat taking 3 to 48 hours. Any kind of chat program would work, though I would recommend something like roger wilco/teamspeak or some other voice chat.