I've used Ranish and it has worked pretty well. I'm afraid there hasn't been a new version in awhile though... Not sure if that makes a difference for you or not.
If it is RedHat then yes, you need a special program to resize NTFS. The only free tool I know of is ntfsresize from the Linux NTFS project. I would imagine you can find it on the latest Knoppix or INSERT CDs.