A word of Caution: When you try to install it on Jaunty you’ll not be able to login to your machine untill you follow the steps carefully and change “root” to “uuid”.

Let’s being…

1. Bring up a terminal window by hittin ALT+F2 and typing “gnome-terminal” (without quotes).

2. Type the following on your terminal:

sudo apt-get install grub-pc

Click enter to install Grub 2 and will modify the existing grub boot loader menu.

3. Reboot your machine.

In Jaunty Grub 2 modifies the existing configuration incorrectly and we are going to change it. After rebooting at the “Chainload into Grub 2″ menu item press ‘e’ to edit the configuration and change:

root   xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx

to

uuid   xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx

Press Enter and then press ‘b’ to boot into Jaunty. Once you have successfully booted from Grub 2 you can install Grub 2 on your machine by hitting the following command on your terminal window:

sudo upgrade-from-grub-legacy

All should be fine after this and you have your new Grub 2 to rock with. Following is how your grub 2 will look like

If you mess up something, follow the steps here.

Update

As Brian mentioned in the comments, you can make your Grub 2 look better in graphic mode. Check here to pimp up your Grub 2. Thanks Brian!