Given that Wormtail was the secret keeper for the potters, it may be that Harry will need to track him down in order to get into Godric's Hollow. I don't know, given that he lived there when he was a baby. Maybe that's what Dumbledore meant, Harry will need Wormtail to tell him where it is in order to access something from there. Then again, would the house there just be a ruin? Hagrid seemed to allude to the house being wrecked after Voldemort's attack.