OK here is a quick introduction to some very cool websites that will let you listen to music online - each has it's own incredible features so have fun exploring!

http://pandora.com/
Pandora is your personal online radio station (or you can call it an internet jukebox) that only plays musics according to your taste. You tell it what song or band you like, they choose the tunes to match your preference. Then you help it along by voting what you like and don't like. Works great. "Social radio" at it's finest... so far!

http://musicovery.com/
Another personal online radio station cum jukebox - you choose the music you like by cool categories such as: genre, mood, decade, popularity, and danceability!

http://www.slacker.com/
Online radio - choose by music category.

http://songza.com/
Super simple: you pick the exact song you want to hear (from a huge selection) and then you listen and enjoy!

http://www.jango.com/
Simple to use "social radio" - choose a station (a pre-mixed selection of artists), or artist - and you are ready to enjoy!

http://www.deezer.com/
Listen for free to any song you like. Create playlists and rate songs. Share your faves. Repeat as often as you like or until the boss catches you procrastinating!

http://www.purevolume.com/
Listen to cool new bands. You can even legally download free music from signed and unsigned artists. Free signup required.

You still here? Not enough online fun with music yet? OK wise guy, try this list of links from Technology Magazine!