Pajama Time! by Sandra Boynton

If you have kids, you should have Sandra Boynton’s books.  They are fun to read, zippy and they all turn into songs as you’re reading them.  My kids have loved Pajama Time since they were about 6 months old, probably in part because both my husband and I like to read them.  The only drawback to this book is that if you really are trying to get them to go to bed, you have to moderate the exuberance with which you sing the song :)