This is a great article, written for DanceMatters, from the London Grid for Learning's Bob Usher. He has worked with the Ballet Boyz and Richard Alston company to create online dance resources for schools. Although the resources referred to are protected by password (someone has to pay for these things somehow!) – if you are in school then they are well worth a look. One of my favourite 'snapshots' is an explanation from the Ballet Boyz about the difference between classical and contemporary ballet.