GRUB Reinstall

[Lee McLain]

Hi all,
      I have my laptop dual booted with XP Home and Hoary and I want
to reinstall Windows and change it to XP Pro(I don't want to upgrade
it, I want to reinstall.)  I know that if I do this, the XP installer
will kill the MBR and GRUB will be gone.
     My question is: How easy is it to reinstall GRUB and get the
settings that I had before?
     If there is anyone out there who has done this, please, could you
tell me the steps to do this or maybe point me to a location to do it?
 This is obviously an operation that I have never done before and I
don't want to screw everything up and have to reinstall EVERYTHING!.

Thanks,
Lee