Phishing becomes one of the most widespread online threats. Fraudsters try to acquire information such login/password, credit card details by masquerading false sites as a trustworthy ones. These sites look the like original ones and have analogous web addresses like google.com and gooqle.com. Fortunately present-day web browsers have better security than some year ago and have phishing blocking systems. This article is about ways to protect your computer against phishing in Mozilla Firefox.
First of all Firefox 3.xx has built-in anti-phishing system. It is active on default. To make sure you should go to Options > Security.

To test this system you can go to this page. Unfortunately this system doesn’t provide absolute security. And it is recommended to use some additional tools. One of them is Liberty Guard 1.47. To use this add-on you should register an account on Liberty Reserve’s site.

Liberty Guard panel is located at the bottom right corner. When you are on real site it will blink green to let you know that you have not opened a fake Liberty Reserve (phishing) web site. According to official source the list of phishing web sites are updated every hour. There is special system that helps you to report new phishing web sites and malicious web sites (Tools > Liberty Guard > Report a phishing website)
Another add-on is IDND 1.5.3

It also places a special panel that tells you whether you are visiting a Traditional Domain Name (green TDN) or an International Domain Name (UN-blue IDN). IDN’s can be used for phishing or spoofing, so suspicious domain names cause an alert box.
As you can seen these add-ons has much in common. Besides there is a number of good alternatives like Netcraft Toolbar, PhishTank SiteChecker, Petname Tool.