How can I block links from another website to my website?

There are some sites out there that "steal" your content by dynamically pulling your content into their iframe (website).   The idea is that they get free content with no work, and maybe get a few $$ in advertising clicks from it. 

If you have an .htaccess and access to mod_rewrite, you can add these lines to the .htaccess file in your document root:

RewriteCond % ^http://.*offendingwebsite\.com
RewriteRule .* - [F]

This forces a "document forbidden" message to the browser and will make the perpetrator's website break.