One very comfortable solution to that problem is provided by http://drupal.org/project/fblikebutton. Unfortunately the positioning of the button isn't flexible enough for my needs.
I want every single node of one certain content type to have a FB like button at its bottom, making the base+node-url like-able. Facebook provides some snippets for that. Since I know that loading many iframes makes the site load very slow, I'ld like to add the JavaScript snippet into the appropriate template file.
My questions now are, in what template file exactly would I inject the little snippets and how do I have to customise the url in the plugin to make it fetch the url of every single node dynamically?