Not sure I agree with the assessment that Apple is a monopoly. While they might currently have the corner on the potable music player market, they hardly have an advantage in any other market. Additionally, their players are just interoperable enough by using the MP3 standard that I doubt they could really be considered anti-competitive. Finally, I really think the iPod is coming the end of an amazing run (over 3 years now) and it can’t sustain it…at which point the monoploy question becomes moot.
Of course, it doesn’t help us much for them to limit the formats they support, but as long as the iPod plays MP3s, then we’re ok. Ideally Apple would release some kind of API for the iPod to allow for more streamlined integration – but that will never happen.