The current anti-phishing partnership between Google & Mozilla that's embedded into Firefox 2 may take another step forward in Firefox 3. ComputerWorld has a summary of a bunch of dev blog posts on the subject of blocking known malware sites much in the same manner that phishing sites are blocked now. The good news is that the devs are already in discussion about potentially overstepping their bounds, so hopefully that bit of caution will be considered for the final release.

"... the feature is currently rated P2 (Priority 2). By Mozilla's definitions, only P1 features are mandatory for Firefox 3.0."