[elxrr]

That's App Engine for Business which is determined by "intranet users in your Google Apps domain." The service is free for a fixed quota set by App Engine, you pay extra for a billable quota, for resources used above the fixed quota.

App Engine for Business: http://code.google.com/appengine/business/

Terms:http://code.google.com/appengine/terms.html

Quotas:http://code.google.com/appengine/docs/quotas.html

Billing FAQ:http://code.google.com/appengine/kb/billing.html