Here’s a list of links that helped me grasp the Web Audio API. Have fun!
simple tutorial about playing sounds, using filters, changing parameters, loading samples into buffers: http://www.html5rocks.com/en/tutorials/webaudio/intro/
the web audio api specification should be your main reference document: http://www.w3.org/TR/webaudio/
note that some of the names are different for Safari and Chrome.
there is a fix called monkey patch for dealing with these differences.
writing your own scriptProcessorNode (web audio uGen):
when using these self written nodes in a graph of other nodes you may find out that they have some limitations compared to normal nodes (in terms of garbage collection). Here an explanation of working around these: http://sriku.org/blog/2013/01/30/taming-the-scriptprocessornode/#vanishing-script-node
dat.GUI can be a nice start to make a quick GUI, don’t forget that making your own is not that hard with HTML5 and jQuery.
video of Chris Rogers, showing off some the api using some nice demo’s and talking about the history.
Keep an eye on this website for future experiments !