If you want it in pokemon pearl,ask your friend if he has a ds and if he has heart gold. If not buy one. If you want it in pokemon emerald,go to youtube and just type 'How to get to Navel Rock in Pokemon Emerald with no Cheats' if you want a mew in pokemon leafgreen, beat the elite four 12 times and you will find it wild in cerulean cave.There are many. After you get mew, you will find celebi wild in victory road.