According to the Messiah2 usage guide, you can play out of region DVD's with the use of Gameshark2/v2, Action Replay2/v2, or DVD region X.
Check out
http://www.messiah2.com/ , under the install section. The install guides list the full usage of the M2.
Unless you are asking about a NTSC PS2 playing a NTSC DVD movie. In that case, you just boot the PS2 in DVD mode.