Trading Pokemon from earlier generations to later generations?

Question

I have a Visual Gameboy and a No$GBA and I have the following question:
Let's say you want a Charmander in a game that is not LeafGreen or FireRed but you know that you will probably need to beat the game to erase the trade restrictions. So, what is required to trade Pokemon from the first generation to games like Emerald, Platinum or HeartGold (subsequent generations of Pokemon)?
For example, if I want to trade from LeafGreen to Platinum, do I need to beat Platinum first or LeafGreen to do this trade, or both? Or is not possible?

Answer 1

If I'm understanding the question...

You need to beat Platinum, there's no need to worry about the Gen III game. You basically need a normal DS or DS Lite, where you put the Gen III cartridge into the GBA slot and Platinum in the DS slot. You go to Pal Park (which is only available post-game) in Platinum and start migrating your Pokemon!

However, it should be noted that you CANNOT migrate Pokemon with VisualBoyAdvance or No$GBA, it must be used with a hard copy versions of the games. Sorry.

Hope I helped. :)
Source: Experience