NOTE: THIS PROMO HAS ENDED: The promotion on the external site has ended, but if you still want to play Angry Birds for Free on PC, then see this page: "Where can I get Angry Birds for PC for Free?"
The promotion starts tomorrow and will likely be over within 30 minutes so if you are a huge fan of the series, you may want to try to get in quick.
For instructions on how to get the game, for free, check this (via SD):
1) Click here
2) Download Intel App Up software from that link and NOT from Intel website.
3) Create new account and you will get notification in you browser that Angry birds is free to download.
4) Old accounts won't work.
Angry Birds has sold over 60 million copies via iOS and Android.