Hi,
The content seems to be the same though, so if they are the same sites, why don't you just 501 redirect all traffic to
www.debian.com to
www.debian.org?
Just one line in .htaccess will do it - unless there are pages that are different on the two sites.
As well as getting rid of the rather unfriendly security warnings (how many people leave when they see this?) it would also improve your search results, as search engines will see the two sites as duplicate content.
Other than that, Debian is a great Linux distro!
Regards
Adam