So it seems from a post on the Google Base blog, plus some background on Google's main blog. According to Google:

For buyers, this feature will provide a convenient and secure way to purchase Google Base items by credit card. For sellers, this feature integrates transaction processing with Google Base item management. We're starting with a very small number of sellers and we expect to include more over the next several months.

There's a page here to get notified when it's public. Here's Bill Burnham's analysis on the potential impact on eBay and its PayPal unit--which he thinks will be huge.

Before it's here, it's on the Bloomberg Terminal. LEARN MORE