eMusic/J is a cross-platform, open source download manager for the eMusic.com music service. It takes the .emx file that you get from the eMusic.com website, and downloads the music specified in it. It can easily work with Firefox or other browsers to make downloading songs and albums simple.
Note: this program is in no way affiliated with eMusic.com. Don't expect them to support it. If there are any issues with it, bring them to the attention of the author.
The old eMusic download manager for Linux was very buggy, hard to make work, and frankly not very nice. So this was an alternative for Linux users. With support from Naxos for their use, it was brought to Windows and Mac OSX also.
To get it, simply go to the Download page, or Download version 0.28 here: 32-bit Linux, 64-bit Linux, PPC Linux, Windows, Mac OSX. The download page contains useful information if you are a first time user.
Having problems? Check out the Troubleshooting page.
For the curious, here is a screenshot of what the program looks like.
There is also a bugtracking system. Go there to let someone know if you've found a bug.