We have a SharePoint Installation (MOSS, IIS 7.0, Windows Authentication, Windows 2008) and Google Analytics has been installed to track site usage. The site is an intranet site, and all users are authenticated before gaining access.
Is there any way in Google Analytics to track user information so we can see details of the login names of who is accessing content?
No, and it's against their terms of use so I guess they are not adding this as a feature. From http://www.google.com/intl/en/analytics/tos.html :
PRIVACY . You will not (and will not allow any third party to) use the Service to track or collect personally identifiable information of Internet users, nor will You (or will You allow any third party to) associate any data gathered from Your website(s) (or such third parties' website(s)) with any personally identifying information from any source as part of Your use (or such third parties' use) of the Service
This data is tracked by default in the IIS logs on the WFEs in your farm. My recommendation would be to use Log Parser to extract the information you're wanting out of those logs on a regular basis to get that kind of usage data.
Todd Klindt has a good blog post on the subject that should get you started: http://www.toddklindt.com/blog/Lists/Posts/Post.aspx?ID=85
