in
My Computer / Shared Documents
I made a folder
and managed to share that along ethernet cables through a router
with my Ubuntu computer
but i dont know how i did it!

from command line:
mkdir -p /mnt/some_mountpoint_name
mount -t cifs //your_xp_system_name/sharename -o username=user_name,
password=myPassword /mnt/some_mountpoint_name

you should then be able to see the share contents

sharename must be shared on the XP side first

share folders in XP and install samba in Ubie.

Works fine with me.