Qbox is a cool startup that I advise. It's a social music play that allows users to access and play free music through their player/application. You can either download it for your desktop, embed a player on your blog (e.g. Xanga, Blogger:), or as they just launched several hours ago on your Facebook profile. What's cool is that typically a video from YouTube or another social network plays in the embedded player, so your blog or site becomes more active and lively.
Here are some screenshots from my Facebook profile:
I didn't post this before, but VentureBeat referred to them in a longer piece on online music sites, "38 free/cheap music sites — Welcome to the fray, Qbox!"