by breeding two raichus
get a pikachu from viridian forest breed it with a ditto and hatch the egg
Volt Tackle is an egg move exclusive to Picju and its evolution family. To get a Pichu with Volt Tackle, breed a Pichu and give one of its parents a light ball.
In Ilex Forest, by Event only.
The only way to get one is to breed a pikachu. The resulting egg will hatch into a pichu.
Pichu
By breeding a female Pikachu or Raichu with a male in the same egg group. Though if you're talking about the special Spiky Eared/Notch Eared Pichu, that event has long since passed, and you will need to trade with someone who has gotten the Pikachu Colored Pichu/Shiny Pichu event Pichu and bring it to Celebi's Forest Shrine.
Breed Pikachu with Light Ball to get Pichu with volt tackle you can also interact in Ilex Forest
It's impossible to encounter a wild Pichu in Pokemon Silver. The only way to obtain one is to Breed 2 Pikachu of different gender, or a Pikachu and a ditto, and the Pichu will hatch from their egg.
First catch a ditto and a pikachu(you can get pikachu in viridian forest in kanto)then put them in the day care. Then run around for a while then the day care man will ring you and tell you your Pokemon is holding an egg.The egg should hatch into a pichu
You get it at Gamestop, but this event is already over. Sorry guys that did not get it!
You can trade for it at the GTS. (Global Trade Station)
Pretty sure baby Pokemon cannot be found as field Pokemon.