How to stop other sites from opening your site on their page

Hello all,

I’ve noticed there are some sites that provide links to blogs and other sites, but when you click on the links, those other sites open up under the header of the “host” site, which often contains advertisements. Not sure what this practise is called, but I’m thinking of about.com as one example (not all of their pages, but I’ve seen it on some, such as goparis.about.com).
I was wondering if there’s anyway to prevent another site from “hosting” your site on theirs and basically making money from your content.