I'm not sure how helpful this is but, roll20 is extremely good for online Table Top gaming. It's completely free, and it has a virtual "table" that you can set maps/images on, move tokens, etc. It has a chat system the includes virtual dice (/roll 4df for Fate/Fudge dice), records, a place to keep most basic character stuff (skills, aspects, items) where everyone can see them, as well as cameras/voices if you want two separate means of communication (one IC and one OOC).
I don't have much experience with it, a friend says it's really good, though the one disadvantage is that there aren't a lot of urban/modern maps for the site (which makes sense since most table tops aren't urban), but since The Dresden Files is pretty "crunch" light that's not as much of a hindrance as it could be.
EDIT: Looking back, this actually wasn't what you where asking for at all. I misunderstood it appears...
Well, it's still a good set of features that a might be useful for a site your looking at developing.