Not all websites have links to “printable version” like wikipedia. Although many websites have stunning  look, it is really ugly when you try to print them. Some parts of the pages will be missing or the format is totally a mess. Instead of waiting the website owner realize this and prepare printer friendly pages for you, you can try to use the “web developer” firefox plugin to solve this problem. Just install the plugin,  then on the web page you would like to print, right click your mouse and find the menus shown in the following picture, choose display CSS only for printer. The web page will become fluid and ready to be printed.

web_developer_right_click_menu