well i would dare to guess that this does not happen *every* time you upgrade, but just when fedora updates give you a more recent kernel. When a new kernel is released it is "added" to your system instead of "replacing" the previous ones, so if something breaks you can also boot older kernels.
the selectable list GRUB (the bootloader) uses is:
Code:
$ su -c 'cat /boot/grub/menu.lst'
you could remove some in that list to just not see them anymore or you could uninstall older kernel with a packagemanager to remove them completely.
stefan
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