I started playing the music bit of my mobile (i detached the colourful moving bits) to Jack when he was about 6 months old and I wish I started sooner, it only goes for 20 minutes (just enough to get him past the first light bit of sleep) and plays Mozart, Beethoven and Bach. I have found this to be the best thing I did in regards to putting him down cos even now that he is nearly 2, when I put that music on, he knows is bed time.