I have the same setup. If you don't have an extra drive partititioned or your current drive is already partitioned you're screwed and will have to reformat the drives.
Remember that NT (with less than SP 4) acts weird when it comes to drives over 7.8 GB too.
There's a great doc on http://support.microsoft.com/support.../q243/8/96.ASP
on partitioning the drives and then look here: http://www.linuxdoc.org/HOWTO/mini/Linux+NT-Loader.html
on how to get the DOS MBR to look elsewhere for LILO
Essentially you set up a small DOS or FAT-16 partition, then install NT. Then if you install ATAPI.exe like it says you can make a big HDD. Other wise you have to make
an empty partition between the small DOS one and the rest of the extended partition.
If you have 98 and NT up and running already and don't want to mess with them then you might as well go buy a new drive.
When you install LILO finally, install it on /boot, not on your /dev/hda1 drive because you will blow away the wiindows boot section and you will be totally screwed.
I'm not the dumbest guy in the world and I experienced every gotcha known to man. Luckily I had a fresh machine and had no prior data that I had to be concerned about. It's pretty tricky but once you get it done with no hitches it's a breeze.