Though the Microsoft Xbox 360 console is not region-locked, many game developers opt to include region coding within the games themselves, which renders games playable only on Xbox 360 consoles with the same country of origin. Fortunately, a handful of games have been released that lack any region-specific coding and can be played on any Xbox 360. There is currently no legal way to enable every game from all regions to be played on a single Xbox 360.
Select and search out whatever game from the NTSC region you are interested in playing. Reference http://wiki.xboxic.com/Region-free_Xbox_360_Games to view a colour-coded list of what games are playable.
Shop for the desired NTSC game online. Shipping costs between countries can raise the price considerably, but buying used games from reputable online retailers can help offset those costs.
Insert the NTSC game disc as you would any PAL disc and play the game.
Set the television set's video settings to 60 Hz if the controller seems unresponsive.
Seek out an NTSC Xbox 360 if you find that the game you are interested in is not region-free. Make sure that you have a television set and power outlet that can accommodate the NTSC Xbox 360.
Do your best to ensure that games are in good condition before buying them online.
Modifying your Xbox 360 voids your warranty.