Use Your Google Account as an OpenID
You can now login to any website that supports OpenID using your very own Google Account.
google account
Do You Maintain Multiple Google Accounts ? Solve That Headache of Logging In and Out
A Google Account gives you access to all Google goodies including AdSense, Analytics, Blogger, iGoogle, Gmail, Google Groups, Picasa, Web History, Google AdWords, Google Checkout and more. But you can run into problems if you have opened more than one account.