You can use them anywhere you like really. Music is a little more subtle than a traditional product, so you don't want to over play them and be like... "hey, look what other people think of my music"... at least not so directly.

The way's I incorporate them are...

1. Use them as quotes on a squeeze page.

2. Create a post that is designed to get a lot of positive feedback in the form of comments and include it in your funnel. That way people see the social proof, but you let them discover it on their own.

3. Mention the comments in an email or blog post, but in a more natural and story telling way. IE, I got this comment from someone the other day and it made me think... and so on. That way you get the social proof without looking like you are trying too hard.

But really anything you can think of that makes sense to you may be worth trying. I just don't think you want to use customer reviews in the same way a traditional product would use testimonials. They serve different purposes. Press reviews is another matter though. I would create a press page for that and possibly link to that right in your nav bar.