You have to mount the drives. Drives have a device assignment in linux.
/dev/hda - ide0 master
/dev/hdb - ide0 slave
/dev/hdc - ide1 master
/dev/hdd - ide1 slave
Scsi drives (or I think SATA, though I don't have that) are:
/dev/sda
/dev/sdb
/dev/sdc
etc.
To read the contents of a drive, you must mount it. To do so, use the (surprise) mount command.
Example: Say I want to mount partition 4 of the master hard drive on ide1, assuming it's an ntfs partition, to the directory /mnt/foobar. Note that the mount directory must already exist.
mount -t ntfs /dev/hdc /mnt/foobar
Now if you go the the /mnt/foobar directory (you can name it whatever you want) you will see the files on that partition.
Types of filesystems supported and their linux names are: (There are MANY more, these are some common ones)
msdos FAT16
vfat FAT32
ntfs NTFS
ext2 linux ext2 (the most common linux filesystem)
ext3 linux ext3 (ext2 with journalling)
reiserfs reiser fs, used by some linux versions, fast when you access lots of small files
iso9660 standard CDROM filesystem