As a music fan I love to discover new stuff. The way I used to proceed was listening to all sorts of radios (local trendy stations, satellite radios, internet radios, etc.). Podcasts gave me a new kind of pleasure through keywords research helping fintune the selection.
Then I found Pandora, a customizable internet radio. Pandora is a website founded by Tim Westergren, award-winning composer, musician and record producer who is obsessed with helping talented emerging artists connect with the music fans most likely to appreciate their music. But don't you think this is just another internet radio with topics and channels playing stereotype playlists. This system is open and evolutive and is a real tool to help you discover music you like. Pandora's music discovery services are based on The Music Genome Project™, the most sophisticated taxonomy of musical information ever collected. It represents years of analysis by our trained team of musicologists, and spans sixty years of music.
All you need to do is register freely, input an artist or song you like and wait for the system to suggest and play similar or related music. You can rate the music to finetune the search. CNET has an "How to..." video that explains it all and an article that focuses on the evolution of Pandora. This thing is just... FANTASTIC !