FaceTime is coming to the Mac.

Steve Jobs has just announced it at the Back to the Mac event, but eagle-eyed spotters would have realised just before that, as the icon was showing during the iLife demo.

“FaceTime makes video calling to or from mobile devices easy for the first time”, said Jobs. “We’ve sold more than 19 million FaceTime-ready iPhone 4 and iPod touch devices in the past four months, and now those users can make FaceTime calls with tens of millions of Mac users”.

FaceTime on the Mac takes your contacts from your Mac address book, and you can make calls to iPhone 4 users, the latest generation iPod touch users and, of course, other Mac users.

In the app, you can go full screen, and display landscape mode as well.

A beta release is available today. It requires Mac OS X Snow Leopard and is easy to set up with an Apple ID.