Yep! You can listen live to whatever is hosted on there. It's definitely not everything, but I bet a solid 75% of US-based radio stations are on there. Can't speak much to non-US radio, but I have listened to some stuff out of Germany before.

Another cool one is the site n10.as. It's a volunteer radio station out of Toronto (I think). It's primarily reruns these days, but there are still some folks doing live shows.