I'm fairly certain some people might already know this, so if you do, don't read this. I just don't want people saying, "I already knew this..." in the comments.

Ever wanted to transfer a Pokemon from Platinum to SS somehow? There's two ways to do this. One way to do this is to trade the Pokemon from Platinum/SS to a freind, then have them trade it to your other game.

Another way is to use the GTS. Here's some steps on how to trade Pokemon from Platinum to SS or vice versa.

Step 1: Take note of both Pokemon's names/nicknames, level, and gender and write them down. Also, make sure both Pokemon are registered in the Pokedex. If you haven't registered it in one game, you can't trade for it.
Step 2: Go to the GTS and offer the Pokemon with the lower level. For example: If I wanted to trade a Lv. 100 Palkia for a Lv. 5 Eevee, I would offer the Eevee. (This is to ensure yout Pokemon will not be lost.)
Note: You want to be specific when typing in the Pokemon you want. That way no one else can trade for your Pokemon.
Step 3: Go to the GTS in the other game, then search for the Pokemon. Once again, BE REAL SPECIFIC. That way it'll be easier to find the Pokemon.
Step 4: If you found the Pokemon, then trade for it. Then you're done!