lol, those are some pretty specific links there.
hey matt, are you inquiring about php4 or php5, .. php5 has a simple xml object that basically puts an xml feed into an object. then there is a document object ( not to be confused with the javascript dom ) that allows you to create xml. i believe i found a good tutorial on zend about that. sorry i don't have a more specific answer than that.
if you are looking for a php4 solution, the only advice i have is to check out the pear libraries. i know there are some xml classes that were made in pear that should work well for you.