Sorry I can't give you the direct link, it automatically redirects

http://www.newsknowledge.com/ go to second link "Content Network" then scroll down to "Search sources"

If you use the newsknowledge service it's $40, but if you browse or search categories - they show all their sources which you can then add directly to blogbomb yourself.

Also I don't know whether this one has been mentioned.

http://www.waypath.com/directory/dmoz/dmoz.html

Brenda