dual boot vista and ubuntu

If you install vista first, then you can install ubuntu directly. Ubuntu can add vista system to the Grub boot loader automatically.
If you install ubuntu first and want to get vista, you should be careful . Because vista dont add ubuntu to its bootloader.
Before install vista, you should save your boot information. It's in /boot/grub/menu.lst.

To save that file just let you remember the partition of the hard drive, for example, I install ubuntu in the 6th partition on the first hard disk (ONLY ONE) and vista in the 2th partition on the same disk. It should like:

title Ubuntu 8.04.1, kernel 2.6.24-19-generic
root (hd0,6)
kernel /boot/vmlinuz-2.6.24-19-generic root=UUID=3ee4ca11-0ceb-4071-8854-b43f86bf25f8 ro quiet splash
initrd /boot/initrd.img-2.6.24-19-generic
quiet

title Ubuntu 8.04.1, kernel 2.6.24-19-generic (recovery mode)
root (hd0,6)
kernel /boot/vmlinuz-2.6.24-19-generic root=UUID=3ee4ca11-0ceb-4071-8854-b43f86bf25f8 ro single
initrd /boot/initrd.img-2.6.24-19-generic

title Ubuntu 8.04.1, memtest86+
root (hd0,6)
kernel /boot/memtest86+.bin
quiet

### END DEBIAN AUTOMAGIC KERNELS LIST

# This is a divider, added to separate the menu items below from the Debian
# ones.
title Other operating systems:
root


# This entry automatically added by the Debian installer for a non-linux OS
# on /dev/sda3


Because vista rewrite the MBR which is a headfile in the disk. MBR will tell computer whereis the booter. Vista will erase the MBR, so it can not find ubuntu. So we need write boot information in MBR by Ubuntu's boot loader :"grub".
So we do:
1,put in your ubuntu cd
2,restart from cd
3,choose "try ubuntu without any change to your computer"
4,open a terminal
5, in the comand line ,type:
$sudo grub
grub>root (hd0,6) //here you need know which partition is your ubuntu stand.
grub>setup (hd0) //here setup MBR file.
grub>quit
$reboot
6,after reboot computer, you will go into the ubuntu system, now do:
$cd /boot/grub
$vi menu.lst
then add follow code to the last line of menu.lst

title Windows Vista/Longhorn (loader)
root (hd0,2)
savedefault
makeactive
chainloader +1

then restart...