I've just discovered Pandora online. You put in what artists/songs you like, and it plays other songs that are like it. You can add "variety" to your station, so not only country songs play, but can add artists like Pink and Green Day to your original Dixie Chicks.
I've found some great songs that I love. I put in Avril Lavigne, Green Day, Carrie Underwood, Dixie Chicks, Bon Jovi, Gavin DeGraw, Pink and Kate Voegele. It's come up with other great songs that fit with those types of music- Weezer, Bowling for Soup, Guns N Roses, Keith Urban, Smashing Pumpkins, Michelle Branch, KT Tunstall, All American Rejects, and so many more.
You can do a "thumbs up" to a song that you really like, or a "thumbs down" to one that you really don't. You can also choose to not play a song for a month- like one that you sort of like, but don't really want to hear it again for awhile.
I just wish I could specifically request and hear a song. Anyone use Pandora and know how to do that??