At this point I don't want to interface w/ google account, I just would like to know if they are logged in to a google account or not, and then serve slightly different links if they are|aren't. I'm using PHP and strict (where possible) HTML 4.
I hope this is not possible. What you are trying to do is to access the type of information others would not want to share with you. I know this does not address your question directly but maybe there is another way to achieve what you want to achieve?