Are you looking for the /boot partition setup by Fedora? Is this where you wrote your bootloader to at install time?
If so, boot from the FC2 rescue disk and you'll have your system mounted at /mnt/sysimage. Following from this, your /boot partition should be at /mnt/sysimage/boot ..
If you want to copy your Linux bootsector to a file (to use with XP's bootloader, for example) - boot with the rescue disk and use..
dd if=/dev/hda2 of=/bootsect.lnx bs=512 count=1
(Assuming your Fedora install created 3 partitions as standard - for /boot,/ and swap. Therefore assuming /boot is at /hda2 - adjust as appropriate)
Now you can copy bootsect.lnx to your XP C:\ drive and add the following to your C:\boot.ini
C:\bootsect.lnx="Fedora Core 2"
Now when you reboot, XP's bootloader will give you the choice to load FC2. Hopefully this is what you were asking, or I just wasted 5 minutes