Ok I did not find this but a really good friend of mine found it so heres what he said.

Hehehe let me be the first to show you some HALO 3 info that will blow your minds. REMEMBER THIS IS THE PRE-ALPHA STAGE OF THE GAME ANNOUNCED BY BUNGIE

First off here are some new features in the game,

New information from Gamefaqs:

Swedish magazine level has had the chance to play halo 3 in multiplayer and there are 3 levels which is revealed,
Valhalla = blood gulch
High Ground = Zanzibar
Snowbound = Frost bite

New vehicle - Mongoose, mostly for transport 2 persons.

new weapon- spartan laser, hard to use but extremely powerful vehicle destroyer apparentley

- nail grenade, sticks on walls and emits nails into the air.

new weapon - spiker (brute weapon),

your secondary weapon is visible at all times at your back.

New transportation system in multiplayer- man cannon, launches you into the air through air streams, you can still be fired at and you can fire back.

The X-button will have a special use which Bungie will not reveal.

The "legendary edition" is sort of a "special-special-edition" that consists of a Full-size replica of the Master Chiefs helmet that contains 4 DVDs with material.
1= The Game
2=Various documentaries and audio commentary
3=Spinoffs such as "Red vs Blue" and "Spark of Life"
4= ALL the cutscenes from all three games in Hi-def

Now the second batch of info of HALO 3, ENJOY!:

www.xboxportugal.com/index.php?subaction=showfull&id=1161959262&archive=&start_from=&ucat

Hope you guys liked the HALO 3 scoops I got for ya.