i can help you out with creating a shared partition for both OS's to use. i'm not sure about your hardware/current setup, but i'll assume from what you've said that you're using hda1 for windows, hda2 as extended for linux with hda5,6 and 7 for /, /usr, and swap. that's a normal setup. now you'll want to create a new partition using fdisk. some people seem to be afraid of this, but i found it very easy to use. first, go to the command line and as root type
telinit 2
this should take you to single user mode, which means disks aren't usally mounted and stuff like that. type
fdisk hda
and this will take you into the menu-driven fdisk program. type
p
to list your current partitions, and take a moment to familiarize yourself with the setup.
now you want to create a new primary partition, with fs type FAT32 (this can be easily accessed by both OS's) to do this, type
n <---- create new partition
p <---- primary
3 <---- label it hda3 (3rd primary)
at this point it'll ask for first sector and last sector, which will default to first available sector and last available sector (take up any free space left) - if you want to control the size yourself, say create a 5 gigabyte partition, accept the first default, then type +5000M
now change the fs type with
t
c
and review what you've done with p to make sure everything is the way you want it. if you're satisfied, use w to write the partition table to disk, and exit fdisk.
at this point you need to format the new parition, which can be down with mkfs, although i had to download dosfsutils because slackware didn't come with mkfs.vfat (FAT32) included. either way, in the end the command should look something like this:
mkfs -t vfat /dev/hda3
assuming that works, then there's just one thing left to do: edit your /etc/fstab to automatically mount the new partition on boot. use emacs or vi or whatever editor you're familiar with, and add the following line:
/dev/hda3 /mnt/windows defaults,umask=000 0 0
there are actually several different set of options you could use in place of defaults, but i have this setup and it so far it works extremely well for me. type
mount -a or mount /dev/hda3
and presto! you should be able to read and write to this partion from linux or windows!
well, there you go. i apologize if that's a more detail than you wanted, but it's best to have the info and not need it than the other way 'round.
if anything goes wrong, or you have more questions, post up.