not a movie, but if you haven't (and you probably have) read 'World War Z' by Max Brooks, you really need to do that.
i've been hearing rumors about a movie, production's starting, brad pitt's involved, they're rewriting the script, blahblahblah for years now. hope they could do it with some money behind it, would be epic.
anyhow, if you haven't read that book, you don't know how good zombie books/movies can be.