If you know your hard drive designations, it's not a problem. You open a terminal, become root, and type a command similar to:
mount -t vfat /dev/??? /path/to/dir
mount -t ntfs /dev/??? /path/to/dir
Use the vfat argument if the drive was formated with FAT32, and ntfs if formatted as NTFS
Replace the ??? with the appropriate partition (for instance hda1, hdb3, or whatever corresponds with your hard drive setup).
/path/to/dir is the location you want to access the contents at. It can be any directory in your filesystem. Just make sure the directory exists before mounting the partition.
When done accessing it, type:
If you get a "filesystem type not supported" then your kernel is not compiled to support the particular filesystem on the drive.
Linux support for NTFS is read-only (write support is experimental and is usually disabled)
You can also set things up so that the partition is mounted automatically when you boot. Again, at a terminal, type:
Reading that should get you started on setting it up if that's what you're after.