Quick one here, something I find myself doing every time I install Ubuntu on a dual boot machine.

1. Create your mount point, sudo mkdir/media/windows
2. Add a line to /etc/fstab, the one below is for a Windows HDD, with the main partition being sda2 (you can work this out by graphically mounting the partition through nautilus and then running df -h)

/dev/sda2 /media/windows ntfs-3g user,fmask=0111,dmask=0000 0 0

Save /etc/fstab then you can run mount /dev/sda2 to mount the drive. It should mount automatically at /media/windows from now on.