It is hard to find readable documentation on ECMAScript E4X. Adobe's Flex 2 documentation is much easier to read than the E4X specification. Look under Programming ActionScript 3.0 / Core ActionScript 3.0 Data Types and Classes / Working with XML. Of course, you must take care using these documents as ActionScript is (mostly) a superset of ECMAScript.
... until the collector arrives ...
This "blog" is really just a scratchpad of mine. There is not much of general interest here. Most of the content is scribbled down "live" as I discover things I want to remember. I rarely go back to correct mistakes in older entries. You have been warned :)