Internet radio can provide some of the freshest, most groovy tunes you haven't heard before, and it's very customizable. You can choose to listen to rock, metal, hip-hop, dance...really anything you want. Instead of being forced to listen to radio stations in your car that are controlled by major corporations and record companies, listen to what you want.
Soma Fm: broadcasting out of San Francisco, Soma Fm is "14 unique channels of listener-supported, commercial-free, underground/alternative radio. Our mission is to expose great new music to people who otherwise may never encounter it. " Soma Fm is run completely on listener donation, and remains today one of the largest independent internet radio outfits. The channels vary in genre, but a good number of them are dance/electronica/chill. This is a really good station to study to. This station runs like a podcast through your media player, such as Winamp or I-tunes.
Radio IO: "What radioIO isn’t: Corporate, consulted, random, limited, formulaic, set to “shuffle,” restrictive, biased, cooler than you." Radio IO is internet radio that plays handmade playlists by real humans! Each station is unique, and somewhat tailored to listener requests. "In addition to building you these focused yet expansive music channels, we love to interact with you: playing your requests, answering your questions, and finding out about more great music right along with you." This station plays through a pop up internet window.
Pandora: This internet radio is really, really awesome. You type in a song you like, or a band you like, and Pandora only plays songs and bands that sound like your entry. This radio provider is an excellent way to find new artists. You can build an account, and bookmark your favorite songs and artists to review later. This is probably one of, if not the best internet radio outfit.