A collaborative workspace for meeting with colleagues/students who are not co-located, Twiddla provides a lot of bang for your buck where features are concerned.
A Web Whiteboard provides a drawing canvas you can share with others.
And here is an actual Storybird:
Scribblar is an online collaborative workspace, providing whiteboard, audio and chat interactivity.
FlockDraw provides online, collaborative whiteboard spaces.
Rather than a tutorial, see how two people worked in the same environment, more competitively than collaboratively, but it gives you the gist.
CoSketch is a collaborative whiteboard environment which eases synchronous use by adding a ‘chat’ feature.