Kazaa's not worth it if the file isn't _really_ widespread, since everyone's divided among super-nodes, and people connected to one supernode can't see the people on the other supernodes.... I think.
A better bet would be the eDonkey network, or, as was mentioned here, BT.
But someone should really put the ISOs up on FilePlanet, in the non-public section, so that people need to be given a link to find them. That would satisfy the liscence agreement requirements of "friends and aquaintances", as well as negate the issue of having huge files hosted on someone's poor server.