Pokémon Emerald Glitches

Get National Pokemon Before Getting National Dex
First you must have Pokemon Colosseum, a Gameboy Advance, and a GCN/GBA link cable in order to do this. You also have to have beaten Colosseum's story mode. Get a pokemon to trade from Colosseum to emerald and a pokemon from emerald to trade to Colosseum. Open story mode go to the trade center in the basement of the Phenac City Pokemon Center. Do everything the game tells you to and the you'll have a national pokemon without having to beat the elite four. This wont work on FireRed or LeafGreen, however.