I would largely stay out of this - I don't have the time to get involved - but I'll provide the web space and an ftp acount, plus a permanent link from the front page.
It's up to Col. Hardison how it all progresses. I'll keep an eye open in case of potential legal problems, but if this kept strictly as a 'fan-site' thing, there should be no problems.
My advice would be to get a gneral outline set up. Then you can go into more and more detail as you wish. Someone's mapped out Moria? You just throw it onto the 'locations' page. Someone else has fully statted out Legolas? Onto the characters page it goes! But, as I said, it's up to you how you go about it, not me.
It's also up to you as to whether you want to use the d20 STL. Remember,if you want to use the d20 logo, you'll be expected to stick to the terms by WotC; if you don't use it, I'd expect them to be more lenient. My recommendation is that you don't use it.
[Edit - thinking about it - I haven't checked, but I'd be amazed if the d20 STL didn't specifically prohibit you from using IP of another company without permission... take a look at the license, but I imagaine you'll find you can't use it].