From Mac Guides
This guide will allow you to boot Mac OS X Leopard , Windows Vista and Windows XP from the same machine. It's a fresh installation, so don't forget to backup any data you don't want to lose. Also, if you have any external drive connected, turn it off to prevent it's erasure
Mac OS X
- Insert your Mac OS X Leopard installation disc (or Leopard restore disc if your computer came with one).
- Once it has loaded completely, select tools in the menu bar and then Disk Utility.
- In Disk Utility select your main drive (not partition) in the left menu, and in the right side of the window, select Partition. A graphical representation of your current partition table will appear. Now open the drop-down menu under the title Volume Scheme and select 3 partitions. The first one will be for Mac OS X, so format it as HFS+; the last one will be for XP (some strange quirk makes it necessary for it to be the last one, it wont work anywhere else), format it as MS-DOS(FAT). For this process to work, you'll temporarily format your Vista partition, the second one, as HFS+. Once you've named each partition and assigned and written down its size, close Disk Utility and begin the installation of Leopard in its partition.
- After the setup is complete, download and install rEFIt. Restart twice, and the rEFIt menu should appear.
- Insert your Windows XP installation disc (it should have SP2 or SP3, other versions will not work) and select it in the rEFIt boot menu
- When it asks you where to install, select the last partition, it should be called C: and have the size you wrote before.
- Let the installation run, and if during it the computer restarts, select in rEFIt the last partition, not the disc.
- Once the installation is done, boot into Windows XP and install the Boot Camp drivers.
- Insert your Windows Vista installation disc (any version that is not 64-bit will work, with or without SP1)
- When it asks where to install, select Advanced Options, then the third partition in the menu (it's because there's a partition Mac OS X doesn't see but Windows does), and then Format. Then select the new partition and install there.
- Let the installation run, and if during it the computer restarts, select in rEFIt the middle partition, not the disc.
- Once the installation is done, boot into Windows Vista and install the Boot Camp drivers.
- Finally, boot into Windows XP and in the Control Panel open System. Open the tab called Advanced and under Startup and Recovery click Settings.... Under the box called System Startup, uncheck time to display list of operating systems so that XP boots directly into XP. Repeat this in Vista.
If you also want the ability to boot into Ubuntu Intrepid Ibex (without losing any of the other systems) you can download Wubi and install it under Vista. The option to use Ubuntu won't appear in the rEFIt menu at boot, you will have to select Vista first and then you will be able to select between Vista itself and Ubuntu