What have you tried so far?
By the way for future reference installing grub to the root of your Fedora installation will have no impact on existing bootloader but will create the menu file containing the required code to boot the installation ... its then easy to either copy the code to you existing bootloader or add a link to it.
Ed: expect something like
Code:
title Fedora
root (hd0,7)
kernel /boot/vmlinuz-2.6.21-1.3194.fc7 root=/dev/sda8 ro
initrd /boot/initrd-2.6.21-1.3194.fc7.img
to work ... with kernel & initrd updated to suit.