Apple has recently release the public beta version of FaceTime for the Mac. This means that you can connect to iPhones and iPod touch from your Mac and have a face to face conversation. Here at Oniracom we can benefit from this if we have someone stuck at the airport when they are supposed to be at a meeting in the office etc. It works pretty smoothly as it gets all of your contacts from your cell phone and they can FaceTime with you using your email address.
FaceTime still requires you to be connected to wifi on your mobile so no meetings from the beach yet.
Download FaceTime for Mac here