Night of The Living Dead (original and remake), Dawn of the Dead (original and remake (not sure which you've seen)), Day of the Dead, Shaun of the Dead.
No, but if you've ever seen Spaced and know of the character Mike, you'll see that it's his dream movie, except with police and not the army. Basically, lots of guns and explosions.
Looks awesome, but it doesn't come out til Febuary.