just try and mount it...if it's the first partition on your second harddisk, then the device name should be hdb1 right?
make a new place for mounting (be root, I guess you need to be) and mount the winxp drive there:
mount /dev/hdb1 /mnt/winxp
now open the folder /mnt/winxp with some app, like Konqueror or Nautilus or whatever you prefer to use, or just with terminal (code below for the terminal):
if you got what you needed, then just copy everything you wish off to a new place in your linux disc, or whatever you want to do:
cp /mnt/winxp/* /home/yourusername/xp_backup
warning: if you have _lots of files_ in your winxp drive, I suggest you call your friends and have a nice evening, because this may take a while....but if it's not that much, just wait
if you couldn't mount the drive, or the command "ls" didn't produce any good output, then it's time to think of something else...but try that one out. you can't "destroy" anything unless you use remove command (rm) as root with a nice wildcard (*) hehe
try it. I mean, mounting the winxp drive, not the rm-thing...