problems with a LARGE party [4e]

[FoE]

Here's a relevant "Save My Game" column on the subject:

http://www.wizards.com/default.asp?x=dnd/sg/20070706

Really, though, I think the most helpful piece of advice you'll get is to split the group up. Have two DMs running the same dungeon; both groups can then compare notes afterwards and brag/complain.