Where Do You Find That Music

While watching some of my favorite television shows--"Scrubs", "House", "Grey's Anatomy" and "Heroes", I have enjoyed the music used for some of these shows as well.

My question is, since I don't recognize the singers/bands for some of this music, how would I find out who sings what? I one time remembered the lyrics of a song, typed it in Google and then was presented with a lyric sheet that contained the name of the artist and the song. Score!! The song was Anna Nalick and the song is Breathe 2 a.m. And thank God for iTunes and getting to just buy one song---not really sure how the rest of her album would sound, but I liked the song.

There has to be a way to get the music played on certain episodes. Sometimes I've noticed at the end of some of the shows they say things like music provided by....and they'll show the album, named the groups/singers, but more often than not, the don't. So I'm stuck wondering and radio surfing (my car is pretty cool in that the rad/tuner thing shows station identification, artist and song playing). I know I'm easily amused and most cars have this now. But I'm not electronically brilliant and little things like this fascinate me.

Back to what I was asking for help about. How do we find out what songs are played on the shows?