2003-12-19 Security Update and Quicktime 6 MPEG-2 Component Update
Apple has released a 2003-12-19 Security Update in your Mac OS X Software Update. This update is recommended for all Macintosh users:
This update includes the following components: AFP Server, ASN.1 Decoding for PKI, cd9660.util, Directory Services, fetchmail, fs_usage, rsync. and System Initialization.
For more information: http://www.info.apple.com/kbnum/n61798
Apple also posted an update to the Quicktime 6 MPEG-2 Component (also in Software Update). Users who had previous purchased the Quicktime MPEG-2 Component had found that the previous version had (inadvertently?) expired on Dec 15th.