With the most recent update to Safari 3.2, Apple has added support in their user interface for extended validation SSL certificates, or EVSSL.
The problem with Safari 3.2′s implementation is that the UI is quite subtle, way in the upper-right hand corner. There’s no standard as to how to implement support for EV certs in browsers but clearly what Apple has done with Safari is mere compliance, not a thorough consideration of how best to show that information in the browser.
I’m biased but I clearly think Firefox 3.0′s implementation is better. No certificate mumbo-jumbo that no one outside of certificate authorities knows anything about. Clear and obvious language that is readable and understandable by anyone who would use a browser on the Internet.