When Minnesota Public Radio ended the long-running, much-loved The Morning Show in December, many listeners had to learn about Internet music options (or, in the Twin Cities, HD radio, a service that allows multiple broadcasts on the same FM frequency) so they could listen to Dale Connelly and Heartland Radio, MPR's new service based on The Morning Show. Heartland Radio is streamed 24/7 over the Internet, requiring a computer with a media player and a relatively highspeed connection.

Internet Radio and Web 2.0 music services offer a wide, ever-changing array of music of all types. Rather than be limited to Top 40, Adult Contemporary, Oldies, Talk, and other formula radio, we can choose from over 15,000 Internet radio stations. Some are mainstream--MPR, KRCW public radio from LA, NPR, BBC's array, and other broadcast stations--but many are aimed at niche audiences, college students, world music lovers, and others. You can find Internet radio stations listed on Reciva.com, Radio-Locator, live365, and other sites you can find with a quick "internet radio" search. iTunes also lists Internet radio stations by genre.
 

A recurring characteristic of Web 2.0 is personalization and customization. You really see this when it comes to online music. There are multiple sites that allow you to create your own "radio station" based on your music preferences. One of the most ambitious is Pandora, Internet Radio based on the Music Genome Project. The Music Genome Project has analyzed the "genes" of 10s of thousands of songs. You put in a song or artist and Pandora will build you a radio station, suggesting other artists (which you can rate by giving a thumbs up or thumbs down). Pandora will incorporate your feedback and construct accordingly.  

Both Last.fm and Pandora have the social networking part of Web 2.0, too. When you have an account, you can recommend songs, find others who like the artists you do, and other social things.

blip.fm  is another social radio site--become  a DJ, select music and share it with your friends. Add your radio station to your home page, too. 

Other Music Resources

Listen 

Grooveshark

Songza

Other

Can't understand/remember the lyrics? Mashable lists 9 sites for lyrics.

What's hot in your area?

The Hype Machine is an MP3 blog aggregator that gathers all the audio links on MP3 blogs into one place

As your music interests grow, you may want to look into ways to manage your audio files and Internet radio stations. iTunes and a new service called Songbird offer not only listening, but many other ways to browse, organize, share, and expand your collections via their stores. Songbird aims to be Firefox for music--Lifehacker discusses some Songbird plug-ins.