how to write ntfs in ubuntu

i just bought an external hardisk..now, it become a problem to me since that Microsoft Windows can not detect the Ubuntu partition format...what i did was i create 2 partion, one using Ubuntu and the other is NTFS..This way i can use both, where its necessary..one problem though that the ntfs in ubuntu i not writeable...after doing some "googling and tips from a friend, i've found a way on how to write ntfs in ubuntu... (p/s: chown won't do the trick)

make a directory name windows in ~/media (but u have to chown it to make it accessible)
sudo mkdir windows
sudo chown unos:unos /media/windows
sudo chmod 744 /media/windows

connect the hard disk and check your usb device

fdisk -l

unmount the ntfs

sudo umount /dev/sda2

then mount the ntfs using the command

$ sudo mount /dev/sda2 /media/windows -t ntfs -o umask=777,uid=unos

it should able u to write the ntfs partition.hope it will work for you..post me on anything ya