Some footage from the start of Halo 3: ODST has leaked into the world, in French. So, firstly....
***GREAT BIG HUGE SPOILER ALERT***
***WE MEAN IT***
The voice acting is in French, but if you can read (and there's evidence that suggests you can) there are spoilers to be had in subtitles. The fact that we can see the footage is apparently the result of French retailers selling the game early. The rest of us, alas, will be waiting until September 22nd to get our hands on it.
We've got the first couple of parts up below, but there are seven in total if you've got a huge great wodge of time to wile away. The rest are here.