I just ran an rsync from the main sl tree and noticed that a bunch of 
files got deleted from 50/i386/SL/

Sadly the list scrolled off my screen before I could grab it but include:

freeglut-2.4.0-7.1.el5.i386.rpm
firefox-1.5.0.10-2.el5.i386.rpm (the -devel rpm is still there)
fonts* (only 3 are left)

the repodata hasn't been updated so I can't believe that it was intended.

By complete coincidence (I hope) I was just about to install freeglut and 
now yum errors saying that the rpm file is missing...