There is no way to get Missingno in these games like you did in the original Red and Blue; you have to cheat to see it.
And since we can't discuss cheating devices here...
-Answered, closed
EDIT: Okay, I'm just realizing that not only have you already asked this question in the Missingno sticky, but you've ALSO made a thread in GPD AND had it answered. Do not make this thread again.