Instructions
Begin a game in single player mode. Look on the world map for stages that have a "Toad" icon above them. Enter one of those stages.
Look for the hidden Toad. You'll hear him shouting as you get closer, so this will help you pinpoint his position. Hit the box to release him.
Press either "Z" or "B" while shaking the Wiimote to pick up and carry the Toad. He can only take one enemy hit before dying, so be careful with him. Carry the Toad successfully to the end of the stage to determine the type of mini game you'll unlock for rescuing that specific Toad.
Rescue the Toad when the last digit of the timer in the upper left corner is between zero and three to open up a green Toad house on the map. This house has a mini game with a "1-Up" cannon. Rescue the Toad when the last digit of the timer is between four and six to unlock a red Toad house with a mini game involving a "Match" mini game where you'll have to match up hidden cards to unlock prizes. Rescue the Toad when the last digit of the timer is between seven and nine to unlock a gold Toad house with a "Star" reward.