Our group scattered all over a couple years ago, but we've kept playing through free tools such as Gametable and VirtualDaivve (very similar but the latter is more geared towards 4.0) with a simple wiki for group visible documents.
Some sort of voice chat (Vent, Skype, ...etc) is a must, as it allows you to still have those moments of random tangents/rules clarifications without cluttering the actual game log with them.
Edit
HereHere's the requested link for VirtualDaivve. The site design isn't pretty but the tool works well. You can even do fog of war.