I have a need to share small files (>8mb) between a desktop running XP, a powerbook and an iMac, both 10.4.9. Currently I have a shared folder on the XP desktop that I connect to with Finder and it works well. However I would like to use an extra 250GB SATA drive I have around as an external always on network drive. My network is cable modem -> 10/100 router -> desktop and an Airport Express. Then from the AE -> powerbook and iMac. Can I add this external drive via ethernet to the router? Looking around there seems to be some options, by I am confused if they work with mixed networks? MacAlly makes one I think, but not sure if it will work with XP.