New yum setup

[WipeOut]

Admittedly I am asking before I have tried..

How do the new yum repo setups work?

What I mean is in FC1 when i wanted to point to a specific mirror I 
would put in the path of the mirror to where the headers directory was 
located.. The new yum in FC3 seems to be using xml files from somwhere..

Where do I need to point it now? still to the headers directory are are 
there some new directories?

Later