Keep Firefox Updated
As Firefox becomes more and more popular, its security problems will get more play. As said before, its not that Firefox is magically safer than IE...its just not as popular. However, the Mozilla group is quite fast usually at issuing updates. To know if an update exists for you, look for the little red arrow icon in the upper right corner of the Firefox window. If it is there, click on it to download the update. Unfortunately, they do not yet issue patches, so you will need to download the entire package and it will re-install over the old one (you will not lose any settings). After installing, just make sure to restart the browser.
In May 2005, Firefox 1.0.4 was released. 1.0.3 contained bugs. The two nastier vulnerabilities are the Cross Site Scripting which can be used to steal information on you and your online accounts, and remote system access which allows the hackers to potentially take control of your system. The fix was issued very quickly, and its recommended that all Firefox users update their software.