Apple has released Mac OS X 10.5.6 to customers this afternoon.

The 10.5.6 Update is recommended for all users running Mac OS X Leopard and includes general operating system fixes that enhance the stability, compatibility and security of your Mac.

Apple details the changes in this support document. Some highlights include:

- Improves reliability of Address Book syncing with iPhone and other devices and applications.
- Improves the reliability of AirPort connections, including improvements when roaming in large wireless networks with an Intel-based Mac.
- Resolves an issue in which pasting text from a Microsoft Office document could insert an image rather than text.
- 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.
- Mail: Includes overall performance and reliability fixes.
- MobileMe: Contacts, calendars, and bookmarks on a Mac automatically sync within a minute of the change being made on the computer, another device, or the web at me.com.
- Improves reliability and performance for AT&T 3G cards.
- Fixes issues that could cause Time Machine to state the backup volume could not be found.
- Improves Time Machine reliability with Time Capsule.
- Safari: Improves compatibility with web proxy servers.

The 10.5.6 update is available as a free download through Mac OS X 10.5's Software Update.