help@profootballtalk.com?
If you go to the NFL website, the contact link says you should only use it if you have a problem with the website.
Darn good question! I've gone through the NFL website, as well as using search engines, and cannot for the life of me find ANY e-mail address for anyone in the NFL, from the commissioner down to the janitorial staff. Will keep looking, and advise if I find anything.