How to Dual Boot Your Mac
If you're thinking about dual booting you're Mac, the great news is that it's a relatively easy and painless process once you upgrade to Leopard 10.5. Just follow the simple instructions below and you'll be on your way to having a dual personality Mac that works as two machines in one.
Before you even start it's always smart to back up all your important data and make sure you sign on to the administrator account. In addition make sure you quit all applications.On the top right hand corner of your screen you will see a small icon that looks like a magnifying glass. Search for Boot camp assistant and launch it.
Once the boot camp assistant is launched the first thing you will do is create a partition on your hard drive for the windows OS. Boot camp will automatically partition the hard drive for the Windows installation amazingly without deleting the existing Mac OS/X. Once the partition is made you can allocate a custom size. FYI there must be at least 5gigs of free space on both operating systems.
Once that is done you can proceed to install Windows on your Mac. Start and select the "Windows installer" then click, continue. Then insert your Windows installation disk. FYI make sure it is a full install version of Windows, in addition if it is XP only use 32 bit version that has service pack 2 on it.
From here you will be brought to a screen that asks you which partition you want to install Windows on. Make sure you choose C:Partition3 bootcamp fat 32. If you choose the wrong partition you'll overwrite your Mac operating system.
The next screen will require you to format the partition to either NTFS or FAT 32. Rule of thumb, if the partition is bigger than 32 gigs stick with FAT 32. Once that is done, your computer will automatically restart, make sure that when you install the bootcamp drivers for windows, which can be found on the Mac OS/X disk by simply inserting the disk upon boot up.
You will notice that it is much easier when you actually go through the process opposed to reading about it. If you want more detail for Vista or the installation process explained in this how to, I have included links below to give you more clarification.