As far as Tiger’s built-in syncing capabilities are concerned, syncing one Mac with another Mac uses Apple’s .Mac Internet-based subscription service as an intermediary. With a .Mac account you can sync both structured information—such as Address Book contacts and iCal events—and individual files. (See The Elements of Syncing for more about structured information and file syncing.)

As online services go, .Mac provides good value for the money: for less than $100 a year, you get ample online storage—currently 1 GB—to store your synced information, along with a multiple email addresses and access to various other useful items and capabilities, such as Web publishing, shared calendars, private message boards, and online backups. Although you can cobble together alternatives that offer almost everything .Mac does, .Mac’s ease of use and tight integration into Mac OS X makes for a very attractive offering.

But .Mac isn’t your only Mac-to-Mac syncing option. Third-party file software, unlike .Mac syncing, typically can sync information and files between Macs over a local network or via a FireWire cable without any need for an Internet connection. Look to third-party options if you don’t want to pay for .Mac or if you frequently need to do a quick sync between two local Macs, such as a laptop and desktop machine.

The Apple devices in question are iPods, iPhones, and Apple TVs. These devices sync via iTunes rather than with .Mac or iSync because Apple wants to provide a consistent syncing experience for their owners, no matter whether they use Mac OS X or Windows on their computers. This wasn’t always the case: before iTunes 4.8, iSync handled the syncing of Address Book contacts and iCal calendar events with iPods. (In fact, you can still use iSync to sync those items with your iPod if you’re one of the half-dozen or so folk who have Tiger but still use a version of iTunes earlier than 4.8.)

Although the number of third-party applications that sync with Apple TVs or iPhones approaches zero, you can find some that sync with iPods. However, Apple has been extremely protective of their little pocket pals and has been known to change the iPod software in ways that break third-party applications without warning. I’ve found that getting involved in the arms race between Apple and developers of third-party iPod-managing software is usually not worth the effort.

This category consists of mobile phones and PDAs running Palm OS—at least, when you’re talking about sync capabilities provided with Tiger. To sync these devices with your Mac, iSync provides the Apple-branded, Tiger-friendly solution. In fact, device syncing is iSync’s raison d’etre in Tiger, as its About box makes clear: “iSync lets you set up and synchronize iPod, mobile phones and Palm devices.” But if iSync doesn’t play nicely with your device of choice, third-party developers may provide the syncing smarts that you need.

In many cases, you may not need to search for a solution beyond Apple’s: iSync contains the plug-ins to handle most of the different devices you can connect to your Mac. These plug-ins are stored inside the iSync application package itself. Every so often Apple updates iSync’s built-in plug-ins via Software Update; if you see “compatibility with third-party devices” listed in a Mac OS X update, it may well refer to an iSync plug-in update.

In addition to handling most Palm devices, iSync supports over one hundred different phone models. You can see the current list of iSync-compatible devices, along with some device-specific notes, on Apple’s iSync Compatible Devices page at http://www.apple.com/macosx/features/isync/devices.html. To save you a trip online, though, Table 3 (next page) presents the current-as-of-this-writing list.

If your phone model doesn’t appear on Apple’s list, don’t lose heart: in addition to the iSync plug-ins supplied by Apple, third-party vendors can provide their own plug-ins that work with iSync. Such plug-ins, however, don’t usually get installed inside of iSync as Apple’s do; instead, they end up in an optional PhonePlugins directory in either the /Library or ~/Library directory (see Add plug-ins to iSync).

Finally, because Apple has made Tiger’s sync engine available to third-party developers, you can now find third-party software that provides device-syncing capabilities that match or exceed iSync’s, and that work with some devices that iSync doesn’t: one notable developer of such applications is Mark/Space, Inc., who provide the Missing Sync line of device-syncing applications (see Sync with Third-Party Software).