Well, I started the install, got pxeboot to get to the kickstart file, formatted the drive... and then it failed, telling me "unable to read group information from repositories. This is a problem with the generation of your install tree."
A quick google gives me the first hit from a year ago, bug 4372 http://bugs.centos.org/view.php?id=4372, which says there's a metadata problem. Has anyone else run into this today?
mark