Sharing an external hard drive

Hi folks
I would be grateful for any help on this problem. In my scholl we have a wired network running under server 2003.Teachers also have laptops which connect to internet using 4 access points. The teachers do not have to log into the network to do this. I have bought an external drive which I would like to make available to the teachers using the network. Ideally I would like it to be accessible whther they are logged into the network or just using access point. Is this possible. If not I would be happy if they could share it just through the wireles connection and not through the school network.

Thanks everyone
Gerry Hancock