Instructions
Load your "Pokemon SoulSilver" save game.
Play through the game until you defeat Janine of the Fuchsia City Gym. This earns you the Soul Badge, TM84 and the ability to access Lavender Town.
Walk east until you reach Route 15. The game tells you when you change routes in the upper-left corner of the bottom screen.
Continue east until you reach Route 14.
Walk up toward the generator and then head north onto Route 13.
Head east until you reach Route 12. You may need to fight several trainers here, depending on whether you can avoid stepping in front of them.
Continue east until you reach a house. Head north until you reach Lavender Town.