Editable xml with php

hi all.
I am looking at building a dynamic gallery in flash using xml.
That part is cool. cause kirupa rocks.

But what i have not been able to find is how i would go about displaying all xml nodes using php.
delete or adding to them from one interface.
can i do that with php and xml or would it pay to employ some mysql databasing to handle it.

heres a diagram of what i am trying to do.

thanks for your advice?