Here comes Google Checkout !!
The long awaited online payment processing system from Google was unveiled today. Google Checkout (formerly called as GBuy is said to be “PayPal Killer”. It will handle only payments of one cent or more–not micropayments for things costing a fraction of a cent. The service will initially be offered in the United States only, and, unlike most new Google products, it is not a beta test version.
Google Checkout will simplify most of the online transactions because can pay at multiple sites using a single Google ID.
Google and Citibank togather will offer customers a co-branded Checkout option that will provide users $5 and 1,000 “thank-you” points for signing up

Take a Tour of Google Checkout
My Two Cents: I think Google Checkout will pose a potential threat to Amazon and PayPal. Will it be integrated into Adsense ?. Lets Just wait and see what happens