The latest update to Safari was released earlier this afternoon. According to Software Update, Safari 3.2 "features protection from fraudulent phishing websites and better identification of online businesses." You should also note that this update includes the latest security updates.
You can find exactly what changed with the security update by visiting Apple's support note. You can download this update by opening Software Update (Apple menu > Software Update), or by visiting Apple's support website.
Thanks for the tip, Yazdgerd!