Get As Many Legendaries/starters As You Want!:

We all should have ehard of the cloning cheat right? bugt the thing is, is that the cloning cheat makes two pokemon with IDENTICAL stats. and if you want to raise a half-decent legendary, you should know that the minute differences in its stats when you first catch it makes HUGE impacts on your overall stats later on.

this cheat should have been called, 'catch a legendary without actually catching it', because it certainly seems like that!

make sure you are on an empty box in the computer storage system. very important.
go up to the legendary and save infront of it.
then, catch the legendary (easier said than done!). DO NOT save after catching it. go to the pokecenter WITHOUT SAVING and deposit it in that empty box. then change to another empty box and... well, you know what to do! turn it of when the word 'power' appears, as in 'saving...DO NOT TURN OF THE POW...' do not let that word 'power' finish showing up.
if all goes well, you should end up back in front of the legendary, your pokedex will not have the legendary in it, you haven't used up any pokeballs (so don't be scared to use master ball here!) and it isn't in your party. BUT it is in that 'empty' box! go back to the pokecenter, withdraw it, place it in another box then switch to an empty box and repeat if you want!

this trick does NOT work for raikou, entei and suicune, not only because it is difficult to save before battling them, but also because their stats are preset each time you start a new game.

PS i heard that this same trick can be done with the starters (chikorita, cyndaquil, totodile) but i haven;t tried it because my game is glitched up and my first box is a total mess every time i try to use it and eventually all the pokemon inside get deleted.

now, i heard that you might get shiny legendaries, but what if you want to keep (for example) ho-oh at the top of the tower (in case you find a way to get shinies always) but you still want to catch it and use it in battles? here is the answer!

also, when you find the strongest legendary you can be bothered looking for, then you can just release the others that you don't want!