I love NoiseTrade and have gotten some great, free music from them in the past! NoiseTrade provides free music from up and coming artists, allowing them to expand their fan base in exchange. There is a huge variety of artists and music genres, from Christian, to rock, to Indie.
Right now, you can download a fun 25-song sampler album, Summertime, by Josh Rouse. Enter your e-mail and zip code to get your free download. You can also preview the album's songs before downloading and tip the artist if you'd like.