Walk: Pokéwalker
Its base catch rate is 130 out of 255 (higher is easier); the catch rate calculator works out your odds with each ball. For the look, the best colour match is Love Ball, Heal Ball or Dream Ball.
Evolution: Happiny → Chansey → Blissey.
Happiny in every game · Pokémon HeartGold & SoulSilver interactive map (Johto & Kanto)