Tokbox is a free service that lets you talk with your friends over live video. Here's how it works: you sign up and you get your link. When you want to talk with anyone, just give them the link - they click and you chat. TokBox allows you to add this url isn your social network profile, blog, or personal webpage. Anyone who comes to your page and see a "Push to Talk" button. They click it and connect to you in real time using live video and audio.
Site: http://www.tokbox.com/