You've heard of Pandora, right? It's the Web-based radio service that lets you choose your favorite artist or type of music, then builds a custom station for you around that choice.
For example, just type in "Adele," and Pandora will create a whole playlist of songs and artists with similar styles. It's ridiculously cool.
And it's only the tip of the streaming-audio iceberg. (For the uninitiated, streaming audio means music that's delivered in real-time over the Internet, as opposed to broadcast over the airwaves like traditional radio.) With a little know-how, you can access more Internet-radio goodness than you ever thought possible.