If it is /dev/hdb, make sure it is correctly jumpered as the slave on that primary IDE chain. Then you can just go to your /etc/fstab as root and add a line for it.
/dev/hda3 swap swap defaults 0 0
/dev/hda2 / reiserfs defaults 1 1
/dev/cdrom /mnt/cdrom iso9660 noauto,user,exec 0 0
/dev/sr0 /mnt/cdrecorder auto noauto,user,exec 0 0
/dev/fd0 /mnt/floppy auto noauto,user,exec 0 0
devpts /dev/pts devpts gid=5,mode=620 0 0
proc /proc proc defaults 0 0
My /dev/cdrom is actually my DVD. Once you have it in, just do a link from your /dev/hdb to your /dev/xxx on your fstab.