Google adsense protects their publishers interest by implementing security precaustions. One of these is by sending a Personal Identification Number (PIN) to the payment address you have supplied when you signed up when you have earned at least $50.00.

after youve been mailed a PIN number, all your account payments will be on hold until the PIN is entered into your account. You wont get paid until the PIN is entered but you can still have access to your account and earn money. Your accunt will be disabled if the PIN has not been entered within 1 year.

To enter your PIN after you receive it in the mail, log into your Google Adsense account.  Click on the My Account tab, then click on edit.  Update the appropriate field and click submit changes.  It would also be a good time to check your contact information and make sure it is correct.  You’re now well on your way to receiving your first Google Adsense check.