Apple has released Mac OS X v10.4.9, available in both client and server versions for PowerPC and Intel-based Macs. The updates are available for download through the Software Update system preference pane, and can also be had from the Apple Downloads web page.
Specific changes in the 10.4.9 release include improvements to raw camera file support; handling of large or malformed images that could cause crashes; image capture performance; mouse scrolling and keyboard shortcuts; font handling; playback quality and bookmarks in DVD player; USB video conferencing cameras for use with iChat; Bluetooth devices; browsing AFP servers; Apple USB model; Windows-created digital certificates; Open and Print dialogs in Rosetta-based applications on Intel-based Macs; time zone and Daylight Savings Time changes for 2006 and 2007, and security updates.
Apple's website has further details about what's specifically changed in Mac OS X v10.4.9, as well. Highlights include improvements to .Mac sync performance and sync issues; fixes for wake from sleep issues with Bluetooth peripherals; changes to iCal; support for USV Video Class webcams in iChat; iSync support for more devices; WPA2 encryption support in Network Diagnostics; performance issues related to Intel iMacs working on high-speed network switches; improvements to OpenGL graphics reliability in World of Warcraft and more.