For decades people have been listening to the radio over the air with its many commercials and less then par sound quality. Only in recent years has there been a much easier way. Listening to the radio online!
A really nice benefit to listening to radio online is no commercials! Most online radio stations run commercial free, either by displaying audio ads on the screen or by listener donations. To get started all you really need is an internet connection. Different sites have requirements on what software you should have installed on your computer in order to listen, but most don't require any software to be installed at all!
ChristianRock.net is one of my favorite online radio stations. It plays commercial free, high quality Christian rock 24 hours a day.
Another good site is Pandora.com. 
Pandora lets you stream online radio based off of your musical tastes. You start by telling Pandora one song or artist that you like. With that information, Pandora plays more songs like it. You then thumb up, or thumb down the songs depending on how you like them. It doesn't take long for Pandora to learn your musical tastes and only play music that you like.
Musicovery.com allows you to specify what mood and style of music you want to listen to. After you specify the genre and mood of music you want to listen to, it displays a web of all the different songs that are in that genre and mood. 
Those are the internet radio stations that I listen to the most.
