In addition to what's already been posted, I would create a 4th partition formatted as FAT32, to use for data storage, so every OS can Use it. Don't recall Linux being able to see NTFS partitions.
For Partitioning, I suggest you use some third party tool, like Partition Magic. it will make the partitioning easier.
You can Partition the drive in 4 and format them all in one go. Then just boot from the various OS CD's and install per the OS's intructions. Always making sure the OS at the time, runs correctly, and does not have any issues, before proceeding with the next OX install.
Installing 3 OSes only to find that Win2000 was not installed correctly can be a real pain.
As previously mentioned, the order should be Win2K, WinXP, and last Linux. Although I don't know how much support there is in linux for SATA drives.
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Ignorance is not necessarily Bliss, case in point:
Unknown has caused an Unknown Error on Unknown and must be shutdown to prevent damage to Unknown.