Solar System Scope is an web-based interactive that lets the user view the Solar System from a Heliocentric view, Geocentric view, or Panoramic view. In the Heliocentric view you can move a planet forward and back in time to see the relative positions of the sun and planets. It looks like many features will be added to Solar System Scope in the future. Any teacher of Earth in Space concepts should check it out.
You may also want to visit and “like” the Solar System Scope Facebook page.
Click HERE to see some of my other favorite Earth in Space sites bookmarked on Delicious.
Science for All 
Hi,
After the success of SolarSystemScope we have launched a new Watch & Play model
http://www.sunmoonscope.com/
focused on the Sun and the Moon as they appear from the given location of the Earth surface:
– current position of the Sun, its trajectory, time and azimuth of sunrise and sunset
– moon phases, current position and trajectory of the Moon
– seasons, solstices and equinoxes in chart
But the most interesting part is to drag the model in time and watch changes during a day or year.
(polar day and night, analemma and situations on the equator are our favourite)
Enjoy it 🙂