Security Update 2006-001 et al.
Apple tonight released not only a new security update, but also updates to iPhoto (6.0.2), iTunes (6.0.4) and Front Row (1.2.1). Those updates are mainly aimed at Bonjour-enabling Front Row, which has been shown at the intel Mac mini's introduction yesterday.
The security update does quite a few things. Non-surprisingly, it updates LaunchServices (at fault for the security issue with shell scripts cloaked as JPG files) and iChat (which was used to send the "worm" around). So for now: All's fine with your Mac's security again. If you've run the update, that is.