Here's how to connect Google Analytics to your BlogPress blog.
1. Sign up with Google Analytics (it's free) http://www.google.com/analytics/
2. Select Settings > Google Analytics (from the left Dashboard menu)
3. (1) Click the button to login to your Google Analytics account. (2) Enter your Tracking Code. (3) Save changes
4. Within a day or two, you will start to see traffic stats in your dashboard.