They are a commercial magazine.
What do you recommend as a course of action?
I dont have experience in practice with copyright or privacy law, only courses in law school. Here is an article to get you started in an images and law sense:
http://www.nytimes.com/2007/10/01/technology/01link.html and here is a primer in IP law re: images
http://www.wipo.int/sme/en/documents/ip_photography.htm (bear in mind this is only for info and not US law).
The fact that they are a commercial entity - it's obvious they are in the wrong here whether on copyright, privacy or both. I would certainly send them an email explaining that they used an image without giving credit and you are contacting an attorney. In the meantime you expect them to retract the photo from any of their magazines...thats if you want to play hardball, in which case I would go and contact an IP attorney with experience in the areas of internet photos and the law. Generally first consults are free.
A more productive approach may be to contact them first and tell them they are using your image without permission and see how they respond...then go from there -
sometimes diplomacy is more productive than war