They are by theelectriccompany on Youtube and also at pbskidsgo.org/electriccompany
Examples
http://www.youtube.com/watch?v=hgT79qStEl4
http://www.youtube.com/watch?v=I2lW-hKu6qo
http://www.youtube.com/watch?v=XOX6M16_NF8
http://www.youtube.com/watch?v=7W1iL9I3XvU
http://www.youtube.com/watch?v=jfCjasAbvzY
There are many varieties. For teaching reading words and phonics. All free to view.