SLOOH

SLOOH, The Live Online Observatory. It may be the only one of it's kind now on the internet, but sure by far it is the best.
It has free and paid memberships. Free members can have almost all the fun too.
SLOOH offers many things that you can never do at you backyard.  
SLOOH provides an unparalleled opportunity to explore space live by mountaintop telescopes situated throughout the world. Using SLOOH’s patented instant-imaging technology and user-friendly interface, customers of all ages and skill levels can take control of powerful telescopes from their Mac or PC computer and Internet browser. Real-time space exploration is just a click away!

There are mission that you can watch or even interact with all over the day. Be sure you don't miss all the fun and the best images you can get from you home.

Here is the link to the homepage ------> SLOOH's Homepage