Using this method, you can restore any type of existing complete backup of a Windows Boot Camp partition. You can use this method to resize a Boot Camp partition, to change the format from NTFS to FAT32, or to move a Boot Camp partition from one computer to another.

An image-based backup is a backup created with the Disk Utility program. Use this technique for backups when you're storing the image to a volume formatted with the Mac file system, because it's fastest. You can find details of how to create an image from a partition in the Disk Utility program help file.

A file-based backup is the copying of all files in the Boot Camp partition to a folder on your Mac OS X hard disk. Use this technique when you're backing up to a FAT32 formatted removable media device such as an external USB or Firewire hard drive. Making this type of backup is as simple as creating a destination folder and copying all the files from a mounted Boot Camp partition into the folder from within Mac OS X (this will not work from within Windows, as numerous system files are locked during use and can't be copied).

This technique also works with Windows-based imaging that can recover individual files from an image such as Norton Ghost 10, Symantec Live State Recovery, or Acronis true image. Instead of booting to Mac OS X, you use the image utility's bootable CD-ROM, and rather than restoring the image, you select the "restore files" option to copy the individual files from the image rather than restoring the sectors to the partition (which ruins the boot records that the Boot Camp Assistant sets up to correctly chain load Windows on a Macintosh).

Note that when this procedure is complete, the Windows partition will be completely defragmented with a single contiguous area of free space.

Phase I: Correctly create the Boot Camp partition and master boot record (2 minutes)

1. If you have an existing Boot Camp partition, run the Boot Camp Assistant and select the option to restore your disk to a single Mac OS X volume. When the process completes, click the Restart button and reboot your Macintosh.
2. Run the bootcamp utility again. Select "I already have a Macintosh Drivers CD" and click Continue.
3. Drag the partition slider to the size you'd like for a Windows partition and click Partition. Note that if Boot Camp says it cannot move files, you'll have to use a 3rd party disk defragmenter like Disk Tools Pro to defragment your disk, and then try this step again.
4. Insert your Windows XP SP2 CD-ROM and click Start Installation. Boot Camp Assistant will reboot the machine and boot the Windows XP installer.

Phase II – Format the Boot Camp partition: (5 minutes)

1. Boot the Windows XP SP2 CD-ROM. In the Welcome to Setup screen, press Enter to continue, then press F8 to clear the EULA screen.
2. In the Select a partition dialog, select the partition labeled "C:", and press enter.
3. In the file system format screen, select "Format the partition using the FAT file system (Quick)". You must choose FAT in order to be able to restore from Mac OS X. You can convert the file system to NTFS using a Windows utility after creating it with the FAT file system if you want.
4. Press enter to continue when the installer notifies you that it will format the partition using FAT32.
5. Let the file copy operation proceed until the installer reboots.
6. As soon as the computer begins the reboot process, hold down the Option key and select the option to reboot to Mac OS X. If you miss the timing and Windows begins to boot, shut the computer off, then power it on while holding the option key until you see the Mac OS X boot option.

Phase III – Restore Windows (20 Minutes)

1. Open the new Windows hard disk icon on the Mac desktop, select all the files within it, and drag them to the trash. Empty the trash.
2. Open the .dmg file containing your Windows backup or browse to the folder containing your Windows files, and copy the following four files at the root level of the folder to the Windows hard disk first: ntldr, NTDETECT.COM, boot.ini, and PAGEFILE.SYS
3. Select the remaining folders and files and copy them to the Windows hard disk.
4. Reboot into your Windows partition.

[kirkmc adds: I have not tested this. Make sure you have backups of all your stuff before trying this!]