You don't *have* to rearrange your drives again, but it would be simpler if you did.

Aside from redirecting your bootsect.bin to point to the new location, and dealing with GRUB/LILO issues, once you got linux to boot it would complain about not being able to find any partition other than the root partition as the entries in /etc/fstab would reference the old location. All of this is correctable - fairly trivial to an experienced linux admin, but certainly not something I'd recommend for a newbie, especially as the /etc/fstab editing would have to be done with vi which is a bit arcane to the uninitiated.

First off you will need to boot into linux using a linux boot/rescue disk. (bootdisk.com has a selection if you didn't create one yourself)
Then you need to mount your your root and boot partitions somewhere, edit /etc/fstab to reflect your physical changes, edit /etc/lilo.conf to change where the root location is and where the boot sector should be put. Then you'll need to run lilo to update the boot sector on this partition. This is complicated by the fact that whilst you are doing this, you're runing in a chroot'ed environment - so you'll have to take this into account whilst working with lilo.

Finally you'll need to copy the new boot sector to the location that WinXPs boot loader expects to find it.

Ultimately, it's a great learning experience - once you're done you will be familar with the basics of unix/linux paritioning, the concept of chroot, the basics of vi and lilo, and the mount command, which is not a bad thing. But it's probably better to be able to learn most of these things at a more leisurely pace.