I don't have any trouble booting various linux distros with xp. I have four of them on the go, including Blag which is based on fedora.
The easiest way I have found to multiboot is to use a bootmanager to boot all the operating systems. The boot manager is installed to the mbr. You do not need separate partitions for boot files - you install the linux boot loaders to the root partitions not the mbr. With this method you can install/uninstall to your heart's content.
You can install lilo or grub bootloaders to the mbr and boot windows and linux distros too if you so wish although it does get more complicated and time consuming.
Remember, some linux distros do not give you the option to install the bootloaders to the root partition and they will overwrite the mbr.
http://gag.sourceforge.net/