It is in the Safari Zone. You will find it in a building close to the end of the area. Also available in the area is some False Teeth which is given to the owner so you can get Strength.
To acquire Group A Pokemon in the Yellow Forest route (which in this case, are the Pikachus that can Surf or Fly) you have to walk 9500+ steps to be able to encounter pikachus that can surf and you have to walk 10,000+ steps to be able to encounter pikachus that can fly.
You need a water Pokemon and the surf HM
HM03 Surf can be found in the Safari Zone in Fuchsia City.
You can only acquire one Eevee in Pokemon Yellow. If you want more, you'll have to trade with someone.
the Secret House in the Safari Zone
Cut, Fly, Surf, Strength, Flash.
use a Pokemon to get to use "surf" then get to cinnibar island and there you go.
You don't need surf, just the ticket which you get from Bill after helping him change back from a pokemon into a human.
The 7th gym leader in Pokemon yellow is in Cinnebar Island, which is south of Pallet Town. You need a Pokemon with Surf to get there.
Surf (HM4) is found at the final zone in the Safari Zone in Fuschia City
go to the hut at the end of of the Safari Zone in Fuchsia city. he will give you surf.
Surf along Route 6, but they are quite rare...