With Pandora Radio, you get to choose the genre of music you like and you can customize it as you go. If they play a song I don't like, I click the thumbs down icon and it's never played on my station again. If I like a song, I click thumbs up and get it and more like it in the future. Eventually, you'll end up with a playlist (or multiple playlists) that's just perfect for your listening tastes. For example, right now I'm listening to their Classical Christmas preset. I've just heard Once in Royal David's City by the Vienna Choir Boys, and next in the queue is Hark the Herald Angels Sing by the Prague Philharmonic Orchestra. Imagine hearing songs about Christ at this time of year! It's crazy, but it just may catch on!
There are lots of ways you can listen. Personally, I prefer to use it at my computer, but can also listen through the television with my Roku. The service has two subscription plans: a free subscription supported by limited advertisements, and a fee-based subscription without ads. A free account user may reach the streaming limit of 40 hours per month, and continue unlimited streaming by paying $0.99.
Go here for more on how Pandora works.
Go here to subscribe.