use it non-stop. It's not just video chatting, it has a lot more. Great instant messenger (text only), great free VOIP calls (can call people worldwide over the internet for free with pretty damn good reception), and as mentioned before also video chat. My brother who lives in London, me, and my parents who live in Milwaukee try to have a joint video call once a month or so.
We use it at work constantly, it is our preferred messenger system and used for VOIP calls to Asia every day.
This is all free. There are also paid services I am less familiar with but I think you can text people and call "real" phones with the VOIP function. Never used anything paid though.
To use it go to skype.com, install it, and set up a username. It is really easy to use and if people you know use skype you can search for and find them pretty easily.