Guys, can i play xbox 360 games from other regions? i am living in

Singapore(S-E Asia).? If i order games from amazon.com...can i play games which are ntsc...because currently i own 13 games...3 ntsc games, 4 pal games and 6 ntsc-j games? so since i could play ntsc games, i thought i could order games from amazon? but i heard that some consoles are region locked??? and by the way, my xbox 360 is not modded..???