I've been hunting awhile. I heard something about the mansion backlot place but I don't really know. anything helps! thanks in advance
In SS and Platinum,you can find it held by wild Pikachu,also in SS you can find in the Pokewalker course The Yellow Forest
In Platinum go to Trophy garden and catch a LOT of wild pikachu there's a 5% chance that wild pikachu will be holding it.
The best way is to get a pokemon and either paralyze or put ashes pikachu to sleep, then use thief!!! Thats how I got mine, this is in SS You find him at the top of Mt.Silver!!!
His team is really strong so watch out!!!