Spotted via a DigitalPoint Forums thread, you can not add a Google Checkout Referral button to your site. The image on the below shows that I see it in my account:
Here is a sample text link unit for Google Checkout:
And here is a sample banner for Google Checkout:
So what are the details? As the Google Checkout Referrals help page says; you can make a whole $1!
When a user you refer to Google Checkout has an account in good standing and completes a transaction of at least $10 (before tax and shipping) within 90 days of sign-up, we'll credit your AdSense account with US $1. To ensure new Google Checkout users are in good standing, your earnings may be delayed up to 7 days.
Honestly, that seems like a horrible deal compared to becoming a Google Checkout Merchant Referral where you can earn $25 at the start and then $5 for every $1,000 of Google Checkout sales processed by merchants you refer. So if you are going to sign up, then don't use the link above, use my affiliate link so I can make more money.
In any event, from this post we learned that Google Checkout referrals were added to the AdSense referral section and I showed you a text link unit.
Update: Now confirmed by the Google AdSense blog.
- You place the Checkout referral button on your site.
- Someone clicks on the button, signs up as a buyer with Google Checkout using a valid U.S. credit card, and completes a purchase of at least $10 before shipping and tax through Checkout within 90 days. (The current $10 minimum purchase corresponds to our existing $10 promotion for new buyers, so this amount may change in the future.)
- You earn $1.