you find groundon in the embedded tower near the safari zone but you have to get the red orb from mr. Pokemon (blue orb for kyogroe in heartgold)!
you can't get it from the game. you have to either migrate it from a gba game or trade it from soulsilver
talk to everyone in the whole game to get a groundon.
You can find it in Pokemon Platinum, Pokemon Crystal, Pokemon HeartGold, and Pokemon SoulSilver.
after you beat the game go to mister Pokemon and he will give you a red orb for soul silver and a blue orb for heart gold and then go to the embbed tower
POKEMON SOULSILVER come with a poke walker and the Soulsilver game
First you have to beat Pokemon Trainer Red. Then you go to Professor Oak and you get either bulbasuar, charmander or squirtle. Then you go to Mr. Pokemon and he gives you a Red orb if you have Soul Silver or a Blue orb in Heart Gold. Then you fly to the Embedded Tower and find Kyogre in Heart Gold and Groundon in Soul Silver. Then you have to transfer a Groundon (if you got Kyogre) or a Kyogre (if you got Groundon) into your game. Then you go to Professor Oak with them both in your party and he will give you a Jade Orb. Then Fly back to the Embedded Tower to find Raquaza!!! -Game Champion
In Celadon's tallest building.
You cannot battle between a Pokemon Black game and a Pokemon Soulsilver game.
There are actually quite a lot! In normal game play, with no events or trading, you get these pokemon: Lugia, Suicune, Entei, Raikou, Ho-oh (yes, you get Ho-oh too), Mewtwo, Latios, Groundon, Moltres, Articuno, Zapdos!
You cannot get it in the game, however with the pokewalker, you can find it on a route.
you can find ds emulators and game files on coolrom.com
At the beginning of the game you can get a sentret and evolve it into Furret.