What is the best way to allow customers with iPads/iPhones to access bonus MP3s?

I have a website where the customers purchase a Course which includes an E-Book and an MP3 amongst other items. When I launched it in 2007, there were no iPads and very few, if any, iPhones.

Now, just about every customer has one or both of these and they want to access the e-book and the MP3 on those devices.

The e-book appears to be relatively straightforward as I have an iPad/Mac version i.e. epub or they can use the Adobe pdf reader to read the pdf version. There are sometimes issues but not that often.

The issue is with the MP3. The only way the customers can get the MP3 from the website to their device is to 1. save it to their computer. 2. Upload to iTunes on their computer. 3. Sync to their device.

I cannot find any other way of allowing them to access it. I get a lot of support requests as some people find this difficult as many customers are not that computer savvy.

So, is there a potentially better way of providing this MP3 (I also have an AAC version) to iPhone/iPad customers?

Is there for example some way of getting it onto iTunes Store so once they have bought the course from the website, they can access the MP3 directly from iTunes?

But I need to avoid non-customers from accessing it and it must be free for customers. Also, they will need to buy it from my website in order for them to go through the sales letter as the Course is quite expensive otherwise. Just having it on iTunes itself would not be enough.

Or is there potentially another way I haven't thought about?

Any suggestions or advice from Internet Marketers with experience of this situation, greatly appreciated.