I'll just shamelessly rip off halo.bungie.org's news and list them all. The trailer is mirrored at:
Halo Vault
3D Action Gamers
Battleground: Halo (soon)
bungie.org's hotline server at hl.bungie.org
As well as our own hotline server at hl.rampancy.net. Also, Acrappa has put up 35 screenshots from the trailer for those with slooow modem connections. Have fun lookin'!