[AvvY]

http://docs.info.apple.com/article.html?artnum=301984

It includes fixes for:
- AFP, SMB/CIFS, NFS and FTP network and file services
- AirPort and Bluetooth wireless access
- Core Graphics, Core Audio, Core Image, and RAW camera support
- disc recording when creating and burning media
- .Mac sync services
- Spotlight indexing and searching
- Dashboard widgets: Dictionary, Flight Tracker, Stickies, and Unit Converter
- Address Book, AppleScript, Automator, Dictionary, Font Book, iCal, iSync, Mail, and Safari applications
- Disk Utility, Keychain Access, Migration Assistant, and Software Update
- compatibility with third party applications and devices
- previous standalone security updates

Download the 10.4.2 to 10.4.3 update here
Download the 10.4, 10.4.1 or 10.4.2 update here

Late,

[macguru]

A really good way to go is to download the combo update then repair permissions in disk utility before or at least after you upgrade the OS