Sorry, but the ONLY REAL CORRECT way to do this is to back up your data, format the drive and reinstall the OS's. not what you wanted to hear, I know. But looking for quick easy fixes trying to circumvent the correct way to do things will only lead to trouble. That being said..here we go..
Format your hard drive with at least two partitions including one primary partition. Keep the file sysytem FAT if you want to use both partitions in DOS and Win2000, FAT32 if you want to use both in Win98 and Win2000.
Install DOS/Win98 on the primary partition as usual.
Boot into DOS or with a boot disk. (alternatively boot from the Win2000 disk) Insert Win2000 cd and install. When asked where to install choose the secondary partition. When asked which type of installation choose (upgrade or clean install) do NOT choose the upgrade option. Choose a new, fresh, clean install on the extended partition.
After the installation is complete upon reboot you kwill be presented with a boot option screen which will allow you to choose which operating sysytem you would like to start from.
On a side note: Win2k's Disk Administration, it may ask you to write a signature and/or convert to a "dynamic" disk. Writing a signature is fine. Do NOT convert to dynamic. NO other operating system can see a dynamic disk, including DOS.
edit: oops. i thought you had said win98 and 2000. I really don't know why you'd want to keep winme. It is by far the worst microsoft OS there is. You'd be better off running win98 and 2000 or even xp and 2000. but the instructions pretty much stay the same.
gee guys thanks for all the support, well i'll probably dual boot it sometime later this year, I thought spearhead would suck on ME but it runs pretty good