RE: The HG/SS Question and Answers thread
On Route 32, there is a bridge with some fishermen on it. If you surf directly east of them, you will see a small rock between some bigger rocks. Examine this small rock and you will find a Heart Scale.
You can buy Heart Scales on Wednesday and Sunday from Pokeathlon Dome for 1000 Athlete Points each (once per day).
You can import them from the Beautiful Beach Pokewalker route (best chance is between 2000 and 3000 steps).
If you've made it to Vermilion City, head south to where the Gym is, and surf down and right. You will see two boats. Position yourself below the bottom one, in the middle, face the boat and press A for another Heart Scale.