Info from site:
This is a pre-order - Game will be despatched to you on or before the RELEASE DATE of 15TH NOVEMBER 2011 - Subject to change by the publisher.
Halo: Combat Evolved Anniversary is a spectacularly remastered version of the original Halo campaign, created in celebration of the 10th anniversary of one of the most beloved franchises in gaming history. With a bounty of new features including cooperative play over Xbox LIVE, a bundle of some of the most beloved multiplayer maps in Halo history reimagined for Xbox LIVE, new challenges and a new story to uncover, Halo: Anniversary is a must-have experience, coming exclusively to Xbox 360.
Developed by 343 Industries in collaboration with Saber Interactive and Certain Affinity, Halo: Combat Evolved Anniversary immerses you in the landmark campaign and genre-defining multiplayer game that helped revolutionize the first-person shooter genre and sparked one of the most iconic science-fiction universes of all time.
Personally this is the only store I have seen where the price is closely set to the rrp stated by 343i reps at E3 2011.