Of the four campaigns I'm currently GMing, only one of them is face-to-face. The other three all use Roll20 as an online host so I can game with friends in other states.
Roll20 is a pretty cool set of tools for running RPGs over the net. It's
got audio, video and text chats, dice rollers and customizable tools
(decks, charts, tokens, API scripts, etc) for automating your mechanics,
and a virtual table top with live-updating for your maps and tokens.
I'm pleased with it. It's still not quite as good as running a game in
person, but the tools are good enough to almost consider using them
instead of dice and minis at the tabletop. If you're going to be running a game online for some reason, I strongly recommend Roll20.
Here's a partial screen shot from yesterday's session.
The setting is Scion, but the rules are FATE. Tracking down a lead, the PCs broke into a Museum after hours. So I grabbed a map I found online of the Chicago Field Museum, and slapped it down on the virtual tabletop. The Curator of Antiquities had an eyepatch, so clearly that meant he was evil. :) They eventually caught him performing a creepy ritual with the bodies of mummified children, about which I had prepared a virtual handout with some disturbing images.