The following is just a brief listing of some sites that are very good starting places. Each of these sites has links to many other places of interest. Captions lead you to other information. Cassini to Saturn Galileo to Jupiter Missions to Mars Lunar Prospector to the Moon Stardust to a Comet NASA sites with the latest news of planetary exploration Que' tal in the Current Sky A Skywatcher's Guide to what's up each month. An extensive list of other astronomy web sites US Naval Observatory Clock Want to know the exact time.
Many satellites are visible to the naked eye.
Now you can take part in the Search for Extraterrestrial Intelligence. You can use your computer to help process the huge quantity of data being received by SETI in its search. An interesting site that shows the misconceptions about astronomy topics that appear in the news and in TV and Movies.