Slideshow with sound. Please help

programming flash
1

Hi,
I want to understand how this NY-times slideshow synchronize the sound with the photos. It seems that the images and sound being loaded seperately (.xml?). But how make the right speech come with the right image?
Any help please?

[link]http://www.nytimes.com/interactive/2008/02/24/weekinreview/20080224_CASTRO_FEATURE.html#section1[/link]

Thanks.