Nik Cubrilovic at TechCrunch has more details of Google's forthcoming payments system, including screen shots of the process. He says:
The checkout process is extremely quick and much faster than Paypal's (page loading times are Google fast) - it also has a much nicer interface making it easier for a user to navigate their way through a checkout and purchase. Overall with Google Base and payments the experience for a user is much nicer than what it is on eBay, a very nice interface and many search features while maintaining the very minimal yet functional interface as expected from Google.