Get AuthSub current user in Zend GData

[mark747]

I'm using Zend Gdata to connect users to a shared Google Docs spreadsheet that serves as a backend to a custom interface.I need to track which user most recently changed the value in a particular column. I'm not aware of a way to do this using Google Spreadsheets (but that would be an acceptable answer to my question). Is there a way to get the username/email address of the user currently logged in through AuthSub, either using the token returned from Google or by another method?