Very simply, Apple has released OSX 10.5.6 via a software update.

Notable improvements include:

- Improves DVD Player performance and reliability.
- Fixes an issue when running the New iCal Events Automator action as an applet.
- Fixes issues that could cause Time Machine to state the backup volume could not be found.
- Improves Time Machine reliability with Time Capsule.
- Improves the performance and reliability of TCP connections.
- Addresses an issue that could prevent Mail from quitting.
- Includes general improvements to gaming performance.
- Includes graphics improvements for iChat, Cover Flow, Aperture, and iTunes.
- Includes fixes for possible graphics distortion issues with certain ATI graphics cards.
- Improves reliability of synchronizing files on a portable home directory.