Not hard at all.
Disk Drake or DrakeX or what ever comes with Madrake/RH should be able to repartition without lossing data or screwing up the Win 2K install. Or you could use Partition Magic, or a copy of notron ghost would allow you to clone the drive to cdr and then restore the drive to a smaller partition.
Make sure you run scan disk and defrag first.
Then install linux....
Make sure to make a boot disk (do not overwrite the MBR, or you will not be able to boot Win 2k).
After install is complete check to see if you can boot to both Win 2K and Linux (using the boot disk)
Then add the bootsecxt.lnx file to you c: drive (remember the exact location)
And edit your boot.ini file to contain a reference for linux.