Heavens-Above: Meeting point for Satellite and/or Astronomy Buffs
This website is definitely a must for anyone seriously interested in Satellites or Astronomy. Chris Peat has developed an extraordinary resource which seeks 'to provide you with all the information you need to observe satellites such as the International Space Station and the Space Shuttle, spectacular events such as the dazzlingly bright flares from Iridium satellites as well as a wealth of other spaceflight and astronomical information. The pages including the graphics, are generated in real-time and customized for your location and time zone.' If you want to participate beyond reading the homepage you will have to register your personal information which, needless to say, I highly recommend.
Source: Heavens Above