Giveaway page here -->
The site is in German, so I will translate:
"Simply enter your e-mail address here and you will receive a license key for the Internet Security 2011 with 365 days license period."
You will see an empty box a little ways down the page. Above that empty box, it says "Please enter your email address here:" In that box, enter your e-mail address then click "Absenden" (Send) You'll receive an e-mail with your license code with the e-mail address you provide.
Note: This offer is valid until 31 January 2012
Thanks to mohammadwasi7861 for the tip.