In Pokemon soulsilver where do you enter the fashion contest?

You can enter the Fashion Contest in Pokémon SoulSilver at the Lilycove Contest Spectacular. It's located in Lilycove City, on the west side of the city, near the Pokémon Center.

To enter the contest, you'll need to talk to the Contest Coordinator at the entrance. You can participate in the different contest categories - Coolness, Beauty, Cleverness, Toughness, and Cute - by choosing the appropriate category at the entrance.