You can also use off-the-shelf software like partition magic or system commander - both run native to windows. There are many more software packages you can use, some are listed in the link I provided, others you can find in a google search for 'resize ntfs' or something like that.
Jul 9, 2004 WARNING! Be careful when partitioning on Linux 2.6 kernels! Partitioning softwares using Parted or libparted MIGHT corrupt the partition table, that MIGHT break the Windows boot process, moreover you MIGHT even lose access to your data from all installed or rescue operating systems. This problem is not NTFS related, we mention this because of the severity and because many people incorrectly believe it is NTFS or NTFS resizing related. These problems can happen using FAT32 or any other filesystem too, or if one just creates new partitions. If your NTFS was resized beforehand then your data is intact. The problems caused by the disk geometry detection code of the Linux 2.6 kernels are recoverable without data loss. Reports are from users of Mandrake 10, SUSE 9.1, Fedora 2, Debian, Gentoo, MEPIS but all other Linux distributions have the same problem using Linux 2.6 and Parted or libparted unless it was independently resolved.