Forum based, "rolls" will really only be done for critical tasks and I have a die roller website link laying around somewhere that actually verifies the rolls so everyone can check to make sure no funny business happened.
As far as time it would be played I'm not going to have set times, forum based games are hard to make work that way because of different time zones, etc. The way I've done forum games I've ran in the past is to try not to progress past key points without input from everyone and then the game master resolving any actions. White Wolf games lend themselves well to forum based gaming because they are more story and character driven rather than rolling die constantly. As long as you don't try to god mod someone elses actions there's a lot of leeway for what you post.
I hope some of the makes sense.
EDIT: I'll post an example of a typical string of actions and resolution later. It would be better than trying to explain it.
Fire, the only player I've really kept in contact with was Taj who RP'd Zeisha and Layla. After some of the fallout from the last time Knight, Mish and Slipknot couldn't play nice with each other I pretty much got the cold shoulder from Mish and Slip. Knight just doesn't seem to be on anymore. If you still talk to Punisher see if he wants in. Oh, and that old Japanese dude with the swords, I can't fricken remember who played his character or what his name was.