Google is about to make more of its services available to organizations with Google Apps accounts. This is an early adopter phase, and all domains may not get this option to move to the new infrastructure.
What this means for you: In addition to the core suite of messaging and collaboration applications, Google Apps users may now access many more Google services with their Google Apps accounts.
Those who are eligible for this early adoption, Google Apps administrator will be presented with the above banner to start with the migration.
In your organization, you can transition selected pilot users and admins, or you can start the transition now for all your users. The transition for pilot users can be reverted if necessary.
After successful transition, your users will now be able to use other Google popular products like AdSense, AdWords, Alerts, Analytics, Android, Blogger, Finance, Google Desktop, News, Orkut, Reader, Voice, YouTube (Full list here).
Also, you can now sign in to Google services from the regular sign-in pages (like http://mail.google.com). Make sure to enter your full email address when signing in.