Oh goody a slack question! Finally somebody with a decent question from a decent linux distro...
Ya sure, this is easy just use the installation cd. Once it gets to the first prompt were it talks about choosing the correct kernel to install with, you know ide or scsi or just press enter for default... You can pass options onto the kernel like which root directory to use... I don't remember the kernel names right of the top of my head but we'll say that ide is one you can use..
ide root=/dev/hda2 (i'll pretend your linux is installed in /dev/hda2)
or whatever... oh ya the linux distro doesn't actually have to be able to read the ntfs partition in order to get lilo to boot into it, all lilo does is just start up the window's very own kernel.
METHOD #2:
For some reason sometimes i don't type out the options to get it to root to the hd and it just boots up normally on the cd like your going to install it...
just mount the hd in a folder, say: mkdir /mnt/slack; mount /dev/hda2 /mnt/slack/
and then copy the lilo.conf like such: cp /mnt/slack/etc/lilo.conf /etc/lilo.conf
then edit the lilo.conf file to point to /mnt/slack/boot/vmlinux instead of just /boot/vmlinux or whatever...
now mind you it's been awhile since I had to do this so I may be of on a couple details, but hopefully it's enough for you to figure out how to fix it...
oh here is a example of my lilo.conf so you see how I dual boot with XP (which has been a couple months since I actually used it

I just need to keep up with windows stuff since I sometimes need to help out the odd unfortuanate windows users)
---------------------------------------------------------------------
# LILO configuration file
# generated by 'liloconfig'
#
# Start LILO global section
boot = /dev/hda
#compact # faster, but won't work on all systems.
prompt
timeout = 50
image = /vmlinuz
root = /dev/hda4
label = SLack
read-only # Non-UMSDOS filesystems should be mounted read-only for checking
# Linux bootable partition config ends
# DOS bootable partition config begins
other = /dev/hda1
label = XP
table = /dev/hda
# DOS bootable partition config ends
-----------------------------------------------------------------------------------------------------------------------
So the first step is just set up windows like usual and then do the lilo thing...
Note, that my kernel is located in the root directory, the default for slackware is in the /boot directory, but I changed it so that when I compile a kernel I don't have to remember to copy it to the boot directory, just because I am that lazy and stupid.
hope that at least points you in the right direction...