I found this extremely annoying! I've never had to wait 48 hours just to get a verification email message - they always appear within the few minutes. For instance, when I filled out the request for the $15 Windows 8 Pro Upgrade Offer, I received the email containing the Promo Code almost immediately.
So, my advice to you is to plan ahead. If you want to install the free Windows 8 Media Center Pack on a Saturday when you have time to play around with it, make sure that you order the pack on a Wednesday to allow plenty of time for the email to arrive.
All griping aside, I must admit that being able to get Windows 8 Media Center Pack for free is a very nice little perk.
Using the Add features wizard
When you do receive the email, you'll find your Windows 8 Media Center Pack product key, as shown.
Credit: Images by Greg Shultz for TechRepublic