As reported earlier, most of the the Lavamus network of sites are back up and running (Edit: it looks like downloads are working too, as reported in the comments below) - that includes iSound, Lavamus, and MP3Legal. These sites are all basically the same music provider, just with different names and usually the same music catalog. That is not entirely the case with all of them, though: JustMusicStore has a somewhat different (much larger) catalog; however, it is not back online yet. It looks like they are re-setting up their server : the default Apache page is currently showing if you go to their site.
