SpiralFrog is a music service that promised free downloads when it was first announced. Its debut was supposed to happen in early 2007 but instead it went through a management shuffle and not much else was heard from them. Just out of curiosity to see if anything had changed, I checked out the web site today. And it appears that they have opened the doors to a Canadian Preview.
SpiralFrog will offer free downloads through an advertising-based model. Users would then need to watch some ads prior to downloading a song. To maintain active licenses on songs, regular visits to the site would also be required (more ad watching). It does not appear that users would then be able to burn the songs to CD or to transfer them to digital audio players.
If you live in Canada and are curious, sign up for the preview.