press select and activate cheats then select walk anywhere cheat. when your in the game press r+b to activate l+b to deactivate
hope that helps
action replay.
Nope, sorry you can't find Deoxys in Pokemon Pearl, at least not legitimately. You can cheat and get it by using the Action Replay though.
No, but you just catch it at Route 228 by using a PokeRadar
Almost anywhere using a good rod
Try using the pokeradar, its not perfect but it could lead you to a find.
through an annoying event or cheat using the action replay
If you have no Pokemon, and you (using the Action Replay) have the walk/run anywhere cheat, when you battle, you will sometimes send out the Pokemon Missingno.
cheat or buy rare candy that levels up your Pokemon
search on google or supercheats a lot of cheat webs have that code!
you can breed Pokemon with a ditto to get a baby of the other Pokemon for example: Pikachu + Ditto = Baby Pikchu or cheat using action replay somehow
you will have to catch it in the pal park by migrateing it from fire red and leaf green or you cheat for it using action replay or i-cheat gaming devices
Pal park, migrating from Ruby/Sapphire/Emerald after obtaining national dex