Mozilla has just released version 2.0.0.6 which corrects a number of security vulnerabilities. If you haven't been prompted to upgrade yet, see my last Firefox Update post for instructions.
On July 31, Apple released security updates for Mac OS X, Safari Beta for Windows, and the iPhone. Information about all of these is at the Apple Security Updates page. For more information about how to update your Mac, see my last Apple Patches posting. I also have a post with my thoughts on the security aspects of Safari for Windows. The iPhone can only be updated through iTunes.