Other than voice acting (which just about ANYONE can do)
(1) We are in need of background writers who are vary familiar with the Stargate universe lore/background etc.
(2) We are in need of technical writers who are vary familiar with the Stargate universe tech/ships/weapons/etc.
(3) We are in need of script writers vary familiar with military jargon/lingo/language, primarily for the USAF.
I can do all three no prob. Alas that's the limit of what i could potentially do. if you need reference for my stargate lore knowledge, here's my prior work Fanfiction
as far as modeling and textures and sounds, alas... I know it's the biggest thing you need!
Why don't you post a thread on Gateworld asking for help? It's the biggest SG fansite there is, i'm sure out of all those you'll get a few more hands helping. I'd guess for every 5 wanting to write, you'll get one who knows how to model :p
EDIT: oh one more thing, i can beta test. got the latest SCP pack and millions of mods. I can start right away if you'd like with whatever you do have. (those screenshots looked awesome) I have limted FREDing ability as well.