eMusic is an excellent, long-standing digital music store and one I've been a member of for years, but to say they aren't friendly to GNU/Linux would be putting it mildly. They used to have an official (in permanent beta, but still) download manager but they've since done away with it so there is no official way to download music from eMusic on GNU/Linux.
Since I do some other audio/voiceover stuff on Windows it wasn't a huge deal for me to suck it up and download from eMusic on Windows, but that has since stopped working for no apparent reason. I click download, the download manager pops up, and nothing happens. Perhaps not coincidentally this is precisely the time the Google Music Manager stopped working as well, and also when my Windows Media Center PC stopped downloading guide data. Methinks a Windows patch of some sort borked all this stuff in one fell swoop but I'd rather not be using Windows anyway so I took it as a wake-up call.
Thankfully there's an unofficial, Java-based eMusic download manager called eMusic/J and though it used to work without any additional configuration in the past, due to recent-ish changes in how eMusic does their downloads it had quit working for me too. Today I finally had a few minutes to dig into the situation and get it figured out.
Turns out what you have to do is trick emusic into think you installed the official eMusic Download Manager even though you didn't, at which point you can download the .emx files eMusic uses to tell the Download Manager what to download, and those .emx files can be used by eMusic/J to do the downloads.
Here's the big secret on how to tell eMusic that you installed the Download Manager. You ready?
Go to this URL in the browser on GNU/Linux where you want to use eMusic/J:
Congratulations! You just fake installed the Download Manager. Now when you go to download music from eMusic you'll be asked what you want to do with the .emx file, and you can simply either download it or tell your browser to use eMusic/J to open those files.
Seriously eMusic, I love you guys but forcing people to use a Download Manager that apparently breaks at the drop of a hat when a Windows update is issued is pretty crappy. Luckily using this trick eMusic/J works ... for now at least.