Chris Brenton has written an article for Sys Admin titled "Phishing Solutions". It outlines many good tips for protecting yourself or your users from phishing attacks.
Some of the suggested tools include:
Clam Anti-Virus - Includes support for preventing a good number of phishing attacks.
Petname - Allows you to mark sites as trusted and displays the trust status each time you visit a site.
FraudEliminator - A commercial product that will do essentially the same thing as Petname, with added features. (I like their slogan, "No Phishing Beyond This Point").
There are also many other tips and strategies to prevent phishing attacks, but you'll have to go read it for yourself. Check out Chris's article in this month's edition of Sys Admin Magazine.