For one GParted live for cd is an excellent free drive partitioning tool. Shrinking down a primary will take time depending how much is currently on it. You will want to back things up before attempting this first.
The APC mag articles are incomplete and leave out a few important details on how to see XP added onto an existing Vista installation and making it work. Note that when going to boot into XP in a dual boot configuration with Vista XP will cancel the Vista restore points out. APC mag doesn't tell you that one!
When going to install Vista being the newer version following XP the new boot loader will include XP as a boot option. Once detected by the newer version of Windows the older becomes an option at startup when automatically added into the new version's own boot loader.
GParted has a few platform independent releases for use on both MS and other partition types other than Linux. Create, delete, shrink, expand, and even copy entire partitions from one drive to another. Most live for cd distros will see that on those as well as the separate download found at http://sourceforge.net/project/showf...kage_id=173828
For the actual guide for use see the documentation with screen shots seen at http://gparted.sourceforge.net/larry...es/gparted.htm
Once you have worked with the Linux tool a few times it becomes quite simple to follow. Some additional screens are found at http://gparted.sourceforge.net/screenshots.php