diskutil resizeVolume disk0s2 70G JHFS+ Linux 28.7G JHFS+ XP 50G

This will resize the first partition (OS X) to 70G, and create 2 new HFS partitions named Linux and XP after it. I chose HFS, because diskutil doesn't support NTFS which I want for my XP partition or Ext3 which wee want for Linux. Well just format these partitions later.

If you havent installed OS X yet you can clear your drive and create the partitions in one step by typing:

diskutil partitiondisk disk0 JHFS+ Leopard 70G JHFS+ Linux 28.7G JHFS+ XP 50 0B

This will create three partitions, the last one taking up any leftover space on the drive (so you don't have to specify 50G, because that's what's left over.)

Don't worry about the EFI partition, Diskutil won't touch it.

PART TWO: LEOPARD AND REFIT

This is a simple step. If you already have Mac OS installed on the OS X partition, just boot it. If you don't, quit out of Terminal and continue with the install.

Once you've booted into Mac OS, download and install rEFIt. The current version is 0.10, get it from refit.sourceforge.org. Install it using the installer, make sure you install it to the OS X PARTITION. You might want to go to Customise and check the File System Drivers.

PART THREE: PARTITIONING CONTINUED

Insert your Knoppix disc. Restart out of Mac OS, when rebooting hold Option. From the menu, chose rEFIt.

This part is important. If you skip it, Windows Setup will only display one partition which is NOT WHAT WEE WANT.

From rEFIt, use the arrow keys to go down to 'Start Partitioning Tool'. If it asks you for permission to edit the MBR, hit Y. Now go back to refit, and chose Boot Linux from CD. This will go to the Knoppix menu, when that appears just press Enter to boot Knoppix.

Once its loaded to the desktop, click the blue K button on the bottom left to open the menu and go to System. Open GParted (NOT QTParted).

You need to change the drive to /dev/sda0 in the top right. Once you get your partitions in the list, delete the windows one. Select the new unallocated space and create a new partiton. Make the type UNFORMATTED, this is the most important part. I also selected 128MiB to bo free before  the new partition because it was there before, but I think you might as well just fill up all the space. Apply the changes. Once its finished just shut down using the power button and exchange the Knoppix CD for the XP CD.

If you're wondering why wee had to create an unformatted partition, ill explain. In Windows Setup, there will be 4 partitions, the EFI partition and our 3 partitions wee made. All three are of Unknown type (HFS) to Windows so it can't install them. When you try to, it won't ask you to format it like it would with an unformatted partition, it will say it can't install and to delete the partition and create a new one. The problem is, once you delete the partition in Windows Setup, it won't create a new one because there are already 3 partitions and Windows can't handle it properly. GParted works with EFI so it can handle creating a 4th partition. Once you have an unformatted partition, Windows can format it as NTFS during setup. It needs to format it during setup in order to make it bootable.

PART FOUR: XP

Insert the XP CD and reboot to refit. Remember: it MUST have SP2 already on the disc for it to work! Chose Boot Windows From CD. This will start XP Setup. You may have trouble pressing any key to boot from CD. I didnt have any trouble, it just booted setup anyway. If there is a problem, just connect a USB keyboard and reboot and try that.

After 2 decades when Windows finally finishes 'loading files', you will see the partitions. Chose the last partition in the list and confirm its the right one using the size, press enter. I chose to format completely just to be safe but I think itll work with a quick format.

After it copies the files and reboots to refit, chose Boot Windows From Partition 4 or Boot Windows From XP to continue setup. If you didnt use the last partition for Windows, it will now fail and give you a 'failed to find hal.dll' error. Start over. If you did read, like I didnt, twice, then itll continue setup happily.

After Windows XP is successfully installed, pop in the Ubuntu disc.

PART FIVE: UBUNTU

By now you should know how refit works. Boot into it and boot your Ubuntu CD. The installer will run some things and then ask you a series of questions. When it gets do drive partitioning, choose MANUAL. Then select the Ubuntu partition, mine mas now called Untitled but whatever, and make the following changes: Format it as EXT3, and use it as 'Mount Point /'. Finish up and it will ask for permission to write any changes to the disk.

Later on it will ask you to install GRUB. I chose not to install it to the MBR because OS X wasn't in the list and I didnt know if it would work with/overwrite refit. However, there is no other correct option. What I did was destroy my Windows install by putting it in /dev/sda4, which is the windows partition, because when it Boots GRUB, and you tell GRUB to boot XP, it reloads itself. To fix it, I later made a bootable GRUB CD in Ubuntu, and reinstalled windows to remove GRUB. Heres the steps:

1 Boot Ubuntu
2 Go to System > Administration > Synaptic Package Manager
3 Look for mkisofs, check it and press Apply. Wait for the download.
4 Go to Applications > Accessoires > Terminal
5 Type the following lines:

mkdir iso
mkdir -p iso/boot
cp /boot/* iso/boot/

Now check to see if it copied all the files in /boot to /home/USERNAME/iso/boot

cp /usr/lib/grub/x86_64-pc/stage2_eltorito iso/boot/grub

If that doesn't work:

cp /usr/lib/grub/x386-pc/stage2_eltorito iso/boot/grub

mkisofs -R -b boot/grub/stage2_eltorito -no-emul-boot -boot-load-size 4 -boot-info-table -o grub.iso iso

6 Now burn the file grub.iso in your home directory to a CD. Reboot to it using rEFIt to test it.

If it boots Ubuntu, insert the XP CD. Boot to it. Reinstall XP on the last partition and format it as NTFS (Quick) when prompted.

PART SIX: FINISHING UP

Congratulations, you now have a Triple booting Mac with two of the best OSs ever and one that is, well, necessary sometimes. There are just a  few more things to do.

Boot to XP and insert the Leopard install CD. Go to setup and install the Mac drivers. You may also want to do stuff like get updates.
Boot to Leopard and google for Paragon NTFS for Mac. Its a public beta as of now, but this great software lets you read and write NTFS Windows partitions as if it were Mac partitions in Finder.
As for Ubuntu, theres a lot to be done, for instance wee need to get rid of the low-grophics mode it boots in. Go here https://wiki.ubuntu.com/MacBookPro and follow the rest of the instruction for the Macbook Pro, search for a similar page if you have an iMac or Mac Mini.

CONCLUSION

I wrote this tut because it took me so long to get things working in my situation, even with so many other tutorials. If you know where to succesfully intall GRUB, let me know. Also if anything else is wrong, unclear, missing, or could otherwise be improved, please post as well. It took me around 20 hours to get all of this done using trial and error, Ihope this helps speed it up a bit. In total I installed OS X 3 times, Windows (attempts) more than 12 times, and had to download the Ubuntu Alternate CD to get that working ofter 3 tries to boot it. If you find this helpful please digg it or post :)