If you're giving me the choice I'd rather you take the GM role, though with you not having done pbp before, it could be considered baptism by fire. The first thing we need to do is decide on a rules system. No matter how stripped down i is, we're still going to have to have rules. I can do d&d 3e-4e, but any previous versions allude me. I've done a small bit of WoD, but never in a fantasy setting.
It might be best to start with something small--3 to 4 combat encounters and a few skill-based scenarios, just to get a feel for it, and make sure people are going to stick around. I don't think any extra programming will be necessary, just three separate forums; one for game play, one for out of character discussion, and one for character records. Anything more than that would be overkill I think.
-IG