In Emerald, after you beat E4, go downstairs to see the news about the BZZT colored dragon. Pick red option for Latias and blue for Latios. This will be happen 100%. Well, the best way to find it is NOT trying to find it. I search for a few hours after I beat the E4, and not found it. Once, I was going to check my berry in route 123 and find the Latios there. Some of my friends find it on the road east of Mauville. Well, actually it's a random