Here is a quick and dirty extension that lets you insert the Google Tracker information for Analytics. Just copy this into your ~/app_code/extensions folder and then edit the tracker number in the extension management console.
GoogleAnalytics.zip (1.19 kb)
UPDATE (Aug 10th) : I have updated the code to place the Google script at the bottom of the page instead of the header. Please download the latest version.
GoogleAnalytics-v1.4.zip