For those new to Pandora, the gist is this:
"Tell Pandora a favorite artist, genre or song, and it will start playing a whole string of music chosen based on that favorite. Pandora gives you the name of the every song it plays, along with the artist and album information. You can save your selections too, so you can listen to these 'radio stations' based on your favorites whenever you use Pandora without reloading the info."
And, the site is free to use.
(Originally posted 8.5.2009)