How to Dual Boot the Mac
In Mac OS versions X.5 and above, the Boot Camp Installer comes pre-bundled.
It's in Applications, Utilities.
Double click Boot Camp Assistant.
Click through the menu, and click the "Use 32 GB" button when it asks to set up a partition. (Trust me, you'll be happy you did.)
Click the Partition button after choosing 32 GB.
This will take a while. Be patient.
After that, it will prompt you for a CD with the Windows Installation. IT must be a MS branded Windows installation CD, and it often will not work correctly off of a slip-streamed DVD.
Put in this CD and click Start Installation after the CD detects.
The system will install Windows XP like any other PC computer, complete with the blue screens that it uses for the initial steps.
When prompted, it is useful to choose FAT for the partition type, because you can then access the Windows partition contents from within the Mac partition, which is helpful to look at documents on the PC from the Mac.
You'll need the Mac OS X CDs handy for drivers during the 1st boot of Windows. To use this CD to install the drivers, open the Device Manager on the Hardware Tab of the System Control Panel. Choose one of the unknown or other devices that are marked with a yellow question mark. Tell it to find a driver and it will start to use the CD to find the software it needs. It will then continue to use the CD to solve the rest of the driver problems. It may come up with a Boot Camp Assistant Installer too, just click through that install item to install it like you would anything else.
It will want to reboot after installing the drivers.
After the drivers are taken care of, treat this install as you would any other Windows install, which means following the Windows Install Checklist found here.
Make sure to set the admin password and do updates right away.
To switch from the Mac to the PC partition, you can go to your system preferences and choose your startup disk then reboot, you can hold down the alt key at boot, or download and install reFIT which will display a screen at boot to allow you to choose which system to use. I highly recommend the manual install of reFit, and the details are on the website.
To boot from the PC back to Mac, click on the boot camp icon in the task bar near the time.