After your broadcast has been sent and some time has allowed for the statistics to populate, simply login to 1shoppingcart and click on "email and marketing" then on "broadcasts". From this initial screen, you'll see your previous list of broadcasts and some general statistics. For a more detailed report however, click on the "results" button.
Keep in mind for the tracking to take place, the email broadcast must be sent as "HTML" or "MIME"
This will allow you to see how many opens, who opened it and when, click through rate and more. To see who opened it, click the underlined number associated with "opens"