If you want to list directly with Apple then you need a Mac since the software they require you to upload with will only run on Mac (that's right--upload with. The same thing you can do on a website anyplace else). I bought a Mac for this sole purpose and went through six months of headaches early this year in my quest to post books directly with Apple. Every step is complicated, takes forever, and there is NO support from Apple on anything. I think the largest company on the planet could find a few pennies in the budget to hire someone to answer the phone.
I was set up with Amazon and BN and had books up within a day. When I had finally jumped through all Apple's hoops and submitted the book it then sat in "Quality Assurance" status--for three months.
If you are going to post with Apple I highly recommend just using one of their aggregators. (Ingram, Smashwords, Lulu in the US and Bookwire for international)
I have 22 books I was going to post there but after the first one I unplugged the Mac and never looked back. It blows my mind that a company that big could be so incompetent, unreachable, and get away with treating their customers and content providers like such crap. And yes, I am bitter.