In Viridian Forest. If you show one to Lt. Sarge at the power plant between 08:00 and 12:00 you can get his number and then you can see him at the train station in Saffron and he will trade it for a French PIKACHU. Oh la la.
You can find it along the parts of the viridian forest and the power plant. The ones in the viridian forest are around level 3,4, and 5. The one in the power plant is around level 22.
In the Trophy Garden just South of Hearthome City.
Either from Viridian Forest, or with the Pokewalker, which you need 80000w and the National Pokedex to unlock.
Pikachu can be found in the Viridian Forest south of Viridian City.
You can occasionally catch a Pikachu in Viridian Forest after beating the Elite Four
Viridian Forest in Kanto
Oh yes you can find it by googling
you can find Bill in heartgold and soulsilver, but he will only tell you how much space you have left in your PC Box(he's in Goldenrod city
There are some Pokemon you can transfer from Battle Revolution but when transferring from Diamond/Pearl/Platinum, it only copies them and it copies everyone you have within your game and the Pokemon that you transfer are a surfing Pikachu, an Electivire and a Magmortar. In order to get Pikachu with the move Surf is you have to beat the game and with Electivre and Magmortar, you have to enter a code into your Self Introduction and you also get a gold and sliver if you enter both of the right codes in your Self Introduction.
You do not need to show Rayquaza to anyone in HeartGold. In order to get Rayquaza, you need to show Kyogre and Groudon (from HeartGold and SoulSilver) to Professor Oak. In turn, he will give you the Green Orb. With the Green Orb in hand, you can find Rayquaza in the Embedded Tower.
Anywhere you can find a ditto, like below goldenrod (in heartgold), just keep looking till you find one. That is the only legit way I know, unless you get it in a trade.
In Pokemon Heartgold or gold and soulsilver or silver you can find it in viridian forest.
Pikachu can be found in Viridian Forest in Kanto.
Catch a pikachu holding a light ball, or use thief on the pikachu's in the Veridian Forest. When you put a pokemon with static in front you will find the pikachu's more easily
In pokemon fire red, leaf green, red, blue, soulsilver, heartgold, silver, and gold pikachu can be found in Viridian forest. In pokemon Sapphire, ruby, and emerald you can find it in the safari zone
Somehow
you must breed pikachu
No you can't find Pikachu in the Safari Zone.
You can only find Skarmory in the Pokemon SoulSilver version.
to find Blue in HeartGold or SoulSilver go to Cinabar Island next to Seafoam Island and go right next to the Pokemon center.
Groudon is unavailible in Pokemon heartgold trade from soulsilver to get groudon.
No, you can not get registeel in HeartGold or SoulSilver. The only way to get it, is by trading
You can find it in Pokemon Platinum, Pokemon Crystal, Pokemon HeartGold, and Pokemon SoulSilver.