Q:

How do I turn on the new Google Spreadsheets for Service Accounts

I want to use the new Google Spreadsheets with a API service account.   It is easy to turn on for a personal account but how do I turn it on for a service account? 

A:

There is no programmatic method to create new sheets and service accounts cannot be logged into interactively.  Thus new sheets cannot be created by a service account.  You can share a new sheet with a service account however this is somewhat pointless as you can't access new sheets via the Spreadsheet api.