For Google Chrome on Windows and Linux Only: The Chrome Radio extension for Google Chrome makes it much easier to playback online radio streams right inside the browser. The extension is very nifty, streamlined and fits smoothly in the browser without interfering with the user’s browsing experience.
Radio stations can be saved within the extension and can be organized in groups, or say, genres. You can also assign quick access keys to five of your stations so that your favorites stay at your fingertips. The extension keeps track of your most played stations and if you want, will also autoplay the last played station on browser startup. Import and Export of station database is also supported.
Coming to the source of media, you can add radio stations from sites like di.fm, sky.fm and shoutcast. Just copy the playlist url (or stream url) from the webpage and add it to the extension. If you get lost, the extension should help you out with its FAQ page which highlights many questions such as how to add stations, where to find them et al.