From February 27 until March 13, GameStop will be offering rare Pokémon, Jirachi. You can bring in your DS and your Platinum/Diamond/Pearl version to a local US Gamestop and snag yourself a Jirachi just days before HeartGold and SoulSilver release.
The last time GameStop offered Jirachi was through a bonus disc offered with a reservation of Pokémon Colosseum. So, this is a pretty big deal for Pokémon fans. This particular Jirachi, when traded over to HeartGold and SoulSilver, will unlock a special route in your PokéWalker. This special route will allow you to catch special, normally uncatchable Pokémon.