Dual Booting FreeBSD or Linux with XP

Will I have to install either FreeBSD or Linux on a separate partition as Windows XP? And will there be any conflicts and stuff? I wanna use FreeBSD but if there would be problems I'll settle with Linux. I haven't decided which distro yet but that'll be later.

You can actually write correctly to NTFS now. The problem is that you can't change block pointers.

That means you can't do the following:
-change the size of a file if the file would not expand into empty space
-create a new file

You can edit an existing file as long as either the size remains the same or becomes smaller, or the new data isn't fragmented on the drive. It's a big gamble and usually a last resort.