readnews

1. Make 3 partitions (use Disk Utility)
- Mac OS X (EFI with Mac OS X Extended, Journaled partition).
- Linux partition - Unix partition type (will be reformatted by Ubuntu)
- Windows Partition - FAT32 (reformatted as NTFS later)
*NOTE: a fourth partition is created for the EFI partition, this shows up as the first partition while installing your other operating systems.

2. Install Mac

3. Install eRFIt

4. Install Windows XP SP2
- Format drive as NTFS
- Make sure it is the last partition (in this case, 4th).
- When you reboot, be sure to select the Windows drive, instead of the CD.
- Once done, install the Boot Camp drivers.

5. Install Ubuntu
- Boot off of the Live CD
- Opt to use a manual partition scheme. Select the 3rd partition, set to format it and have it mount at root.
- Before you continue, back up your MBR.
- alt-F2 will open a command line then type: dd if=dev/sda of=/tmp/sda.mbr bs=512 count=1
- Continue with the install process, Until step 7.
- Here, click on the “Advanced” button, and enter (hd0,2) for the boot loader install. This will install the boot loader only in the Linux partition.
- Start the install.
- When finished, restore the backed up MBR with this command: dd if=/tmp/sda.mbr of=/dev/sda

That process will let you tri-boot your Mac. My references for each new information can be found below:

Partition order
Dapper install with info on MBR backup
Final information on the Grub issue from which I found out how to reference the Linux partition for the boot loader install.

original source