Talking of suing, what about Apple?
Apple regularly change the iTunes sharing code to try and block third-party applications from using it. Until that happens, though, there are other applications using the same protocol and based on the same work. In any case, I’ll mainly use Blue Coconut at home, as it’s easier to copy songs (that I already own) from a server to my laptop from within iTunes than it is to use the Finder and file sharing to copy them. This strikes me as a perfect example of fair use, and as such I feel that applications that connect to shared libraries are perfectly defensible.
