If you got a router which support external HDD via usb port, you can use any cheap external usb HDDs. There must be some products out there, Asus make this sort of thing which can use as printer server as well, they have two products, both are wireless, one 11b and one 11g, it seems that usb is only for usb1.1. You could check it out your self. Product spec: click here buy (£56) here click here. This is 11g version, 11b version a couple pounds cheaper.
If your interested, e-mail Maxtor through their web site and ask the question.
I would have thought it would appear as a removable drive and then you can share it in the normal manner. For example, I just connected a card reader on my home network, configured it to share, and opened files on my daughters machine, so I see no reason in principal why it cannot be shared.
If you decide to talk to Maxtor, I would be interested in the definitive reply please.