You need Joomla 3.x and php 5.3.1 +
Here are Joomla's requirements.
If your site is not in English, You need a language pack for MyMuse in your language. If we do not have one contact us and we will start a translation.
If you are selling tracks, you will want the tracks themselves and a 'preview' version, often the first 30 seconds.
The tracks can be MP3 or WAV or FLAC or whatever you want. You can sell multiple formats at different prices.
The previews are normally MP3's.