Another option would be to play-by-post in a forum like this. There are several benefits, as I see it, to this approach.
People will have more time to think out what their characters are doing and saying, so better RP element.
Because things move slower, there is no problem with different time zones.
Also, there is a tendency to have less combat, more roleplaying, as the only thing the PbP doesn't handle too well is combat.
I'd be interested in running some PbP at some point, though not 4E (not that I have anything against the system, but it doesn't lend itself to what I want to do in a PbP game.