If you still use Firefox 2 (Firefox 3 has been available for some time), you’re about to lose a security feature. When Mozilla releases the next update to this version of its web browser, it will no longer contain anti-phishing protection. The soon-to-be-released update, version 2.0.0.19, will disable the Google SafeBrowsing support in the browser. This version of Firefox uses a version 1 of SafeBrowsing, and Google has told Mozilla that the use of this version of the feature will be discontinued.
There’s really no reason to continue using Firefox 2, however, unless the system requirements of Firefox 3 prevent you from upgrading. You need at least Mac OS X 10.4 (Tiger) to use Firefox 3, so if you are using Tiger or later, you’d be best off to just upgrade to the newest version of the browser.
