Now available via Software Update:
Security Update 2007-005 is recommended for all users and improves the security of the following components:

bind
CarbonCore
CoreGraphics
crontabs
fetchmail
file
iChat
mDNSResponder
PPP
ruby
screen
texinfo
VPN

Security Update 2007-004 has been incorporated into this security update.

For detailed information on this update, please visit this website: http://docs.info.apple.com/article.html?artnum=61798