Yeah, online is generally region-locked, though there are games that allow you to manually connect to a different region (Motorstorm Pacific Rift is one such game). Wouldn't want to play with spotty-faced Americans, anyway
As for high definition standards, there's no longer the whole PAL vs. NTSC issue anymore, if that's what you mean. Just the two standard HD resolutions: 720p and 1080p (and 1080i, if you choose to include that).