Heart Gold: Do you think my team is ready for the Pokemon League?

This is a fantastic team, but you're missing a Water type. Lapras is a good choice (Union Cave on Friday). You could also go with Gyarados or Vaporeon. Just be SURE TO TEACH IT AN ICE MOVE!!! This is key in defeating Lance. Ampharos first, to get rid of his Gyarados, then send out something with an Ice move to sweep the rest of his team. If he has Aerodactyl, hit it with a Water move (its Earthquake would get rid of Ampharos).