With the advent of robotic telescopes and the wide-scale availability of the Internet in schools, it is now possible to carry out real investigations of astronomical phenomena from almost every classroom in the UK. A variety of robotic telescopes are now available for use online. Some of these are free for educational organisations to use, and others charge for telescope time. In this article we look at three organisations based in the UK (Bradford Robotic Telescope, Faulkes Telescope Project and National Schools' Observatory) that offer telescope access and educational resources, and highlight some of the important differences between the various systems on offer to schools.