Nice, I'll try to convince my brother to
A. Get the wireless adapter
B. Wait to play even longer, and
C. Set up the account first, add you, then start playing.
We'll begin on Medium, and perhaps later after getting used to how the game plays and getting better at it, tackle Hard and maybe *gasp* Legendary. We might have a couple of my brother's friends, so there will be a lot of headset switching involved between the two of us. Speaking of which, can you have multiple headsets for the 360 on the same system, so that when we're online my brother and I can each talk, and would there be some way to distinguish us? Now, if only all you 360 owners can get a PS3 with Resistance 2 so we can do some 8-player co-op as well...
Also, what's your AIM SN Ryan? That might make life easier for actually timing everything, or at the very least we can talk on Skype and my brother can use the headset.