The entire casting list for Rob Zombie's Halloween is online, and it includes major character explanations and some major spoilers.

The plot goes, very simply:

After being committed for 17 years, Michael Myers, now a grown man and still very dangerous, is mistakenly released from the mental institution (where he was committed as a 10 year old) and he immediately returns to Haddonfield, where he wants to find his baby sister, Laurie. Anyone who crosses his path is in mortal danger.

...as for the rest, including the character breakdowns, I'm going to leave that glory for the people who were handed it at Bloody Disgusting. Well done guys. They were also good enough to edit out all the names of those who are killed by Myers in the film, but it's fair to say that some of them you can just guess at.

I've stayed clear from a lot of it and just skim read, some of it hints that we are going to see some uncompromising scenes as we did with Zombie's The Devil's Rejects (review). There also looks to be a heavy reliance on flashbacks.