In addition to the following, also see Installable Web Apps articles.
Supporting Federated Login with Google Accounts for Chrome Web Store Apps
- November 2010
Streamline the authentication process for your users by supporting Federated Login for Google Accounts.
Extensions, Packaged Apps, and Hosted Apps in the Chrome Web Store
- September 2010
Read this article if you're trying to decide whether you should implement an extension, packaged app, or hosted app.