Yesterday, Google unveiled a new service called (simply) Sync that updates your contacts and calendars between your wireless phone and the Google servers instantly and over the air. And guess what: it works! Guess what else: it’s free!

That’s more than can be said for Apple’s $99 per year MobileMe service. I tried MobileMe for three months, and it just never worked. I don’t care about the 10GB of web space (have my own servers, or something like DropBox), I don’t care about the email account (uh, GMail), and I don’t care about the fancy photo galleries (I’ve got Flickr and my own gallery). The biggest thing I need is my contacts and calendar data everywhere, on every computer I use, and on my iPhone. MobileMe failed spectacularly in that respect — syncs were inconsistent, would sometimes replicate data, and just could never be depended upon to replicate data reliably from one device to another.

Google Sync works on the iPhone, Windows Mobile, BlackBerry, S60, and a handful of other devices. It utilizes the broadly adapted Microsoft Exchange wireless sync protocols (thank you, Microsoft) and is relatively easy to setup (Google has basic instructions for all devices). And after more than 24 hours on my iPhone, I’m quite happy with it.

I did have to go through an additional step to tell Google I have multiple calendars I want to sync (otherwise it defaults to just your primary one), but it works fine — even for my account, which is not regular GMail but Google Apps for Your Domain. Now, for example, my wife can add an event to her calendar and I’ll see it instantly on my iPhone, no matter where I am, without having to plug into a computer.

OK, so your mobile device syncs up to the Google “cloud,” but what about keeping all your desktop apps up to date? If you’re on a Mac, you can also now sync iCal with Google Calendar (real two-way sync, not just the one-way subscription that’s been around forever), and Leopard’s Address Book has built-in syncing with your Google account too. That last one isn’t working perfectly for me on one my machines, but it works well enough most of the time.

I remember when the iPhone first came out and Apple made a big deal out of their collaboration with Google. At the time, I made a pie-in-the-sky wish that Google would somehow make wireless syncing work for calendars and contacts, but never really believed it would happen because of Apple’s MobileMe service. However, since Apple included Exchange capability in the iPhone for corporate users, that opened up the door for Google (and others) to use their own tools that piggyback on that protocol. One more nail in MobileMe’s coffin.