One of the most notable improvements that accompanied yesterday's Mac OS X 10.5.6 update was the delivery of long promised MobileMe Push functionality to desktop and notebook Macs.
Despite advertising their MobileMe service as providing Push services from your Mac, Apple's original implementation only offered intermittent sync services. Apple acknowledged the mistake in an apology letter and said they wouldn't use the term "Push" until it was "near-instant".
Mac OS X 10.5.6 has brought this service much closer to the original description. Apple has updated their technote to describe the process as it stands:
Contacts, calendars, and bookmarks sync automatically (generally within a minute of the change being made on the computer, another device, or on the web at me.com).
The "within a minute" syncing is offered to Contacts, Calendars and Bookmarks alone. Other items such as Mail Notes, and 3rd party applications will only sync on an hourly basis, with some data (Keychains, Mail Rules) syncing every 8 hours. These new benefits are not yet available to Windows MobileMe users whose data still syncs in 15 minute intervals.