I read about Soundpedia at Techcrunch for the first time and was pleasantly surprised about the functionality and look of Soundpedia. What I really like about it is that you can listen to complete albums using their music flash player. You can either search for artists or albums using the site search or browse artists and albums by selecting a genre from the sidebar.
The site search and browsing the genres is currently the only way to be able to find and listen to all artists that are hosted on Soundpedia. The method to browse the albums and artists reveals that only a few of them are listed currently.