NTFS-3G is a recently released ntfs driver for Linux, that provides full read/write capability for ntfs partitions. The web site for it is at http://www.ntfs-3g.org/. To install it on my dual-boot Ubuntu/Windows desktop, I booted into Ubuntu, then downloaded the latest version of NTFS-3G using Synaptic.
After applying the marked ntfs-3g installation from Synaptic, the next step is to test the mount process for ntfs partitions, ensuring that the read-write capable ntfs3g driver is used rather than the default read-only ntfs. I edited the /etc/fstab file (for automatically mounting partitions), and made the following changes to the mount line for my ntfs partition:

#new ntfs-3g partition
/dev/sda4 /media/sda4 ntfs-3g defaults,nls=utf8,umask=007,gid=46 0
After saving the file, I unmounted all the partitions, then remounted them, checking to see if they were no read-write.
Here is the result of mount command before change and unmounting filesystems:
/dev/sda4 on /media/sda4 type ntfs (ro,nls=utf8,umask=007,gid=46)

Unmounting and remounting changed /etc/fstab:

#umount -a
umount: /dev: device is busy
umount: /proc/bus/usb: device is busy
umount: /var/run: device is busy
umount: /sys: device is busy
umount: /: device is busy

#mount -a
/media/sda4 type fuse (rw,nosuid,nodev,noatime,allow_other)

Notice that the filesystem type for the mount has changed to fuse, which is the susbsytem used by the ntfs-3g component to manage its read-write access to the ntfs partition. Finally the acid test, creating a file works:
$ cd /media/sda4/temp
$ ls >tefromlinux.txt
$ head tefromlinux.txt
$ ls -l tefromlinux.txt
-rwxrwx— 1 root plugdev 3257 2007-10-28 16:18 tefromlinux.txt

The ntfs-3g driver brings the Linux desktop effort even closer to the objective of being a completely viable alternative to Windows as a mainstream operating system for the general consumer user. I expect that with it in place, I will be spending even more time working in the Ubuntu side of my PC.