For online merchants, Google Checkout is a viable alternative to PayPal. It lets you accept most major credit cards, and you’ll pay less in transaction fees than you do to PayPal.

The main thing you can’t do with Google Checkout is use it in your eBay auctions. At this point in time, it’s strictly a merchant tool, not an auction tool. That said, Google Checkout will save you money over PayPal and similar alternatives, which is a good reason to check out Checkout.