Here is a nice and thorough tutorial on how to use the GRUB bootloader:
From the website:
One of the most frightening things about Linux is the horrible word bootloader. The primary reason for this is the fact that most new Linux users have only ever used Windows operating systems. In the Windows world, they have never bothered with bootloaders. For them, the issue of a system booting was a transparent one. At most, they would use Windows Recovery Console to fix problems for them. Thus, they have been spared the need to learn about the single most important piece of software on a computer – the little program that makes it all work.
Read Article here -> http://www.dedoimedo.com/computers/grub.html
Cross-posted at: http://www.saigonblogs.com/?p=48