Not sure if this will work in a blackout area, but I've tried it today and it works. If it doesn't work in the blackout area, you may have to use the Hotspot Shield option that was mentioned before (I won't know until gametime which way it will work...if at all).
Anyway, if you are NOT in the blackout area and your internet provider doesn't offer ESPN3, you can follow these steps and it should work (again, it worked for me!):
1) Go to att.net
2) Make sure you are logged out of any Yahoo! accounts you have
3) Click on the "mail" icon
4) Sign up for a free att.net e-mail account
5) At the espn3.com page, select AT&T as your Internet Service Provider and sign in on the att.net page with your new att.net e-mail account
6) ESPN3 should now allow you stream events