Google has been known to send email notifications for certain types of payments, like Western Union or some EFT (electronic funds transfer) but it seems like Google has stepped up their email notifications to publishers. In fact, there were reports back in March of this year at the Google AdSense Help forum about emails. But not many since.
Here is a copy of the text of one email:
You've been issued a payment from Google AdSense
Hello Firstname Lastname,
Please note that we've recently issued a payment to you for your AdSense earnings. Your payment represents the total of your finalized earnings accumulated through the end of last month.
For more information, please log into your account and visit your Payments page. Depending on your form of payment, you may also be able to find a reference number there to track or pick up your payment.
Remember, EFT is our recommended form of payment because it is faster and more reliable. For more information, please visit the following link: "How do I sign up for Electronic Funds Transfer?"
Congratulations! We hope you receive your payment soon.
Sincerely, The Google AdSense Team
© 2010 Google
Email Preferences: You have received this mandatory email service announcement to update you about important changes to your Google AdSense account.
Some were worried that the email was a phishing attempt but they don't appear to be. Either way, never click on the links within those emails. Just login directly to your AdSense account and go to the message center to validate the email.
Did you get one?