How to develop WebRTC application for beginners?

EDIT: updated April 2016

For those getting started on ICE, STUN and TURN (and WebRTC in general) I recommend the resources linked to from webrtc.org/start.

Resources for developers working on iOS or Android apps using the native WebRTC APIs are available at webrtc.org/native-code.

Shameless self promotion, but for further information about ICE I suggest you look at the WebRTC Infrastructure article I wrote for HTML5 Rocks.

Another potential resource to consider is the open source Mobicents SIP Servlets project, which provides examples how to write server code for managing WebRTC calls.

Here is a video demo: http://vimeo.com/51744602

Here is a blog how to run WebRTC apps on CloudBees one of the popular Java PaaS: http://www.telestax.com/webrtc_cloudbees/

If you are not a Java developer, you can take a look at Restcomm and keep an eye on upcoming announcements for WebRTC support: https://code.google.com/p/restcomm/