Instructions
Activate the Mystery Gift feature in "Pokemon Platinum." Travel to the Jubilife TV Station and talk to the producer. You must provide him with the secret phrase --"Everyone Happy Wi-Fi Connection" -- to activate Mystery Gift.
Access the Main Menu and select "Mystery Gift." You will see three options: "Get from a Friend," "Get via Wireless" and "Get via Nintendo WFC." Select "Get via Nintendo WFC." You may obtain a Wonder Card through this function.
Attend a Nintendo event to use the "Get from Wireless" option under "Mystery Gift." While at the event, select "Get from Wireless" to receive your Wonder Card.
Utilize the "Get from a Friend" feature under "Mystery Gift" to send or receive Wonder Cards. Your friend should be playing "Pokemon Diamond," "Pokemon Pearl," "Pokemon Platinum," "Pokemon HeartGold" or "Pokemon Soul Silver." Sit in close proximity to your friend when you use the "Get from a Friend" option.
Redeem the Wonder Cards you receive for prizes. Travel to any Pokemart and speak to the delivery man inside to earn your prize.