One of my favorite things on the internet is NPR First Listen. It's a great way to preview new music before its release date. I've found some great music this way. While you can't download it to your computer, you can stream it. Sometimes an album (in its entirety) is available for 2 weeks to listen to as often as you like. The artists are usually updated on the weekly basis. This week the new Devotchka, Bright Eyes, & Adele albums are available among others.