Opera 9.1 will have an in-built real time phishing protection filter.
Opera?s Fraud Protection will work differently than Firefox and Internet Explorer?s (IE) anti-phishing protection. In Opera, when you type a URL in the address bar, while the page is being requested from the web server, Opera will simultaneously access Opera?s database (from Geotrust) to check the legitimacy of the site you want to visit. If the site is determined to be a fraud, Opera will instead display a warning and block you from visiting the site. You?ll still have the option to bypass the warning.
Unlike Firefox, which by default only checks against a pre-downloaded blacklist of fraud sites, Opera does the checking in real-time

Via OperaWatch