BazarSearch от Vojtěch Hořánek

Have you ever wanted to search on multiple websites at a time? Well this add-on enables you just that! With one click of a button you can search on infinite amount of sites. When you open the popup by clicking on the "B" icon in the toolbar, you can enter a search term. After you have decided what you are looking for, click the Search button. A new Firefox window will popup with all the websites you have set up.