Here are some useful firefox add-ons for firefox:

1. Facebook Toolbar Add-on

Integrate your Facebook life into your browser.
Features:

• Search Facebook from anywhere
• Get Notified
• Connect with Friends
• Share Content
• Upload Photos

Download…..: Click Here

2. Facebook Like Button Add-on

Easily share web pages you like with your friends and see how many people on Facebook like the page you are on!

Download: Click Here