MobileMe syncing improvements and security fixes headline the list of changes unveiled with the release of Apple's Mac OS X 10.5.6 update this week.

The file should appear in users' Software Update windows, depending on the frequency Software Update is set to check for new software. The sixth update to Leopard, originally released in October 2007, comes with the usual range of tweaks, bug fixes, and security improvements.

One update of note concerns MobileMe, which is now capable of pushing updates made to calendars or contact information from the Web or an iPhone to the primary Mac within a minute. Apple had numerous problems with the launch of the MobileMe service earlier this year, and the latest update should help fix one of the more pressing issues still outstanding with the US$99-a-year service.

A full list of the issues addressed with 10.5.6 can be found here, while a list of the security improvements should appear here. The update can be downloaded from Apple's Web site, but the Software Update function is the easiest way to get updated.

This article was first published as a blog post on CNET News.com.