Hi,
I find it easier (and smaller) to download the netinst.iso (like
Fedora-18-x86_64-netinst.iso)
Loop-back mount and pull the vmlinuz and initrd.img into /boot
The vmlinuz and
initrd are made available separately here:
http://mirrors.kernel.org/fedora//releases/18/Fedora/x86_64/os/images/pxe...
So you can avoid the loop-back mount. It's a good tip, though.
Sometimes creating a grub entry is the most straightforward way to get
things rolling.
--Ray