>>27050103Personally, i use a DS flash card. Among the other things, it allows you to apply a save over a GBA or a DS save by using homebrews (if the flash card is slot1, you'll need to send the save via ftp from your pc).
So... You can play LeafGreen on an emulator on your pc/phone, save the game, then use a save editor (for gen3 i like A-Save) to export your party/box pokemon files. You can directly import these .pkm files to other gen3 saves, as R/S/E. If you apply the R/S/E save to a real gba cartridge, you can use palpark to move them to gen4 and upward.
If you don't want to palpark all the way to gen6, you can use pk2pk (google for "pk2pk Time Capsule Transfer Tool") to make them from gen3/4 to gen5, then use PokeSav or PokeGen to "inject" them in a B/W save, then use the flash card homebrew to export them in a real B/W cartridge.
They're moved in a hacked way, but they're the very same legit pokemon you captured in-game. You didn't boost, changed IVs/Natures or even edited them in any way: purists may disagree, but I think that as long the hacking is only used to avoid buying hardware and/or losing ages to move mons through generations, it's pretty fine.