It looks like OS X 10.5.6 is now available for both OS X Client and OS X Server. You can download the client combo update here. It’s 669 Megabytes. The OS X Server update is available here. It is 883 Megabytes.
Here are a few of the items that are included:
- Improves the reliability of AirPort connections, including improvements when roaming in large wireless networks with an Intel-based Mac.
- Includes graphics improvements for iChat, Cover Flow, Aperture, and iTunes.
- 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.
- Updates the ssh Terminal command for compatibility with more ssh servers.
- Improves Time Machine reliability with Time Capsule.
You can go view all of the updates that are included with this update here.