You can use Skype if you wish. Somehow I see alternatives gaining traction.
SIP protocol for VOIP supports video from several vendors for free.
I recently had a similar thought. I've been using Skype while living in Germany to keep in touch with my long-distance girlfriend for the last few months. I figured, let's give SIP a go, and give Skype the boot.
In summary: SIP is flaky as hell when both parties are behind NAT. Sometimes it works, but most of the time, it doesn't.
The big thing Skype has going for it is "it just works". No need to forward firewall ports, and no worries about whether it works when one party is behind a particular brand of router.
Needless to say, we've gone back to using Skype. Sorry SIP, I gave you a really good shot, but you just weren't reliable.