Xbox 360 Games Region-Locked | PS3Blog.net
At a pre-TGS press briefing, Microsoft announced that the Xbox 360 will support both region-locked DVDs (of course) and region-locked games (doh!). So if you want to import games from Japan, or any region not your own, you’ll be out of luck unless you do something as dastardly as mod your Xbox 360. My guess is that one of the very first mods for the 360 will be to get around region locking.
I don’t see any reason for region-locking games, except to annoy consumers. But then Microsoft has always been very good at that. (Sorry, couldn’t resist.)