I have a web cam...now how do i chat?

So, I'm very excited for the live broadcast after the commercial kings premier this Friday and in the descriptions they say "chat with us live as we watch the encore presentation of Commercial  Kings" and I wanna chat live!

So, I have a webcam and it works, though it is not compatible with Skype.  But, if I go on Skype I can still talk to people on it using my microphone.So how do I chat on YouTube???? Can someone PLEASE PLEASE instruct me on how to chat live with Rhett and Link! Thanks!