Okay, I did about ten minutes of research. I just read the iTunes EULA. Under the permitted uses and restrictions, it does not say one word about hardware - what you can and cannot use. They state the usual - one copy on your computer, can't put it on a network (so technically, if I don't download a fresh copy for each computer I want it on, I am breaking the EULA), may only use it to reproduce copyrighted materials you are legally authorized to use, etc.
Then, I went to their download pages (both Mac OS X and Windows) and looked at the hardware requirements. There is no requirement to use it only with an iPod, iPhone or iAnything. The requirements for hardware only list the computer hardware the software can run on.
Nowhere does Apple state that I will, at their discretion, only be able to use their software product on their hardware product. Don't you think that's a detail that I, as a consumer should have before I install their software?
Some people have said that iTunes was made exclusively to support the iPod. Please cite your sources for that tidbit, as I haven't been able to find anything about that. As I understand it, Apple makes iTunes freely available to anyone who wants to download and use it, without stating any restrictions on what PMP you may use.
For me, that means Apple is morally responsible to either allow the software to support all hardware, or to change their EULA and their hardware requirements to let consumers know, up front, that they must buy only Apple's hardware to use this program.