this is my xml file

<myxml>
<a>
I can load XML like the wind!
</a>
<b>
I can load XML like the storm!
</b>
</myxml>

i want to trace "I can load XML like the wind!" in flash movie.for this i am using this syntax that is not working .somebody please tell me the right syntax

trace(this.firstChild.childNodes[0].firstChild.nodeValue);