War video...

I found this while I was surfin tonight and found it interesting... Thought I would share it with you guys. Can anybody tell me what the song is from? I know I've heard it somewhere but I just can't figure out where...

http://www.metacafe.com/watch/473986/war_watch_it_if_you_want_to_live/

It reminds me of something that I'd hear on Halo 2.