Not responsible for Lost data! Use at Your Own Risk!

External Links
Using DD to backup your drive
Uninstalling the Boot Manager LILO from the MBR
Uninstalling the Boot Manager GRUB from the MBR

MBR Backup/Restore
Need to be root. I recommend using one of the "live" CDs like Knoppix or Mepis
and mounting a floppy for the 'filename.dd' destination.
Mepis Linux
Knoppix

Backup MBR to a File
dd if=/dev/hda bs=512 count=1 of=filename.dd

Restore MBR from a File
dd if=filename.dd of=/dev/hda

Backup MBR to Another Host
dd if=/dev/hda bs=512 count=1 | ssh user@host "cat - > 20040516-backup-mbr.dd"

Restore MBR from Another Host
ssh user@host "cat 20040516-backup-mbr.dd" | dd of=/dev/hda