Google Safe Browsing for Firefox
Jared point out to me the Google Safe Browsing for Firefox which purports to:
Google Safe Browsing is an extension to Firefox that alerts you if a web page that you visit appears to be asking for your personal or financial information under false pretences.
Considering the fake emails I get claiming to be my bank, credit card company, pay pal or Nigerian Foreign Ministers…. this is probably worth a look-see for most uses.