You need to have Dialga, Garitina and Plakia in your party and then just go to route 201 and you will see a level 50 jirachi
Sorry, you cannot obtain Jirachi in Diamond Version without the use of cheats. You can obtain it via Pokemon Colosseum pre-order disc though.
with mystery gift
You can obtain a Cresslia by trading it from Diamond, Pearl, and Platinum
Sorry, you can't. You have to get Pokemon pearl for that. If you buy Pokemon platinum you can obtain dailga, palkia, and giratina!
It is the same way as Pokemon diamond and pearl because i used this and it helped me a lot!!!!
Turtwig is a starter Pokemon in Pear, Diamond and Platinum or you can obtain through trade
You will get the Jirachi... that's a little obvious. When you transfer Jirachi (Obtained from Gamestop), you will get Jirachi, and a special Pokewalker course called Night Sky's Edge. It has a variety of Pokemon and items you can obtain on the pokewalker.
You cannot find Regigigas in pokemon black and white. You can obtain it by trading with someone who have Pokemon Diamond/Pearl/Platinum.
The only way to obtain it is to trade it from Diamond, Pearl, or Platinum. Once you have it in you game, you can breed it.
You can't obtain a Rotom in Pokemon Soul Silver. Instead, you have to trade it from Diamond, Pearl, and Platinum, and Rotom appears near the TV in the Old Chateau once you get the National Pokedex in Diamond, Pearl, and Platinum.
Obtain 200 Pokemon in Pokemon ruby, sapphire or emerald, then go to professor birch and you get to choose one of the johto starters, then you migrate the starter you chose to Pokemon, diamond, pearl, or platinum.
Jirachi is being given out by Nintendo through Wi-Fi on the DS, but I don't think it works with Emerald/Sapphire/Ruby. It was meant for the Generation IV games (Diamond, Pearl, Platinum). Otherwise, try and find an e-Reader. They can download a Jirachi onto your game cartridge. Sometimes game shops will use e-Readers as a promotional items, so you can obtain them there...But the margin's slight, and Jirachi is probably THE hardest Pokemon to aquire in the entire Pokemon universe. Good luck anyway.