As an active astronomer there are a few websites that I use often. If you are interested in stargazing, then the following may be of use to you. There are many other websites available, so you may find others that you prefer. The ones below are a few to start with that off free information and, are sites that I use regularly. I will continue to add useful links to this blog.
Stellarium – http://www.stellarium.org/en_GB/
The first is actually free software that you can download onto your PC/tablet or smart phone. Most amateur astronomers that I know use it as a tool for finding their way around the night sky and finding interesting solar system bodies or deep sky objects. If you want to know the exact position of the planets for a particular night, or hunt down a comet, asteroid or galaxy then this software is ideal.
Heavens above – http://www.heavens-above.com/
Heavens above is a very handy website for checking out all sorts of astronomical data. You can find predictions for satellites passing over your location (and the ISS) and their brightness. You can also look up asteroids and comets that are currently visible, and importantly how bright they are for that night (comets and asteroids vary in brightness so you will want to catch them at their brightest to stand the best chance of spotting them)
Aurora Service – http://www.aurora-service.eu/
If you are lucky enough to live in an area with very little light pollution then this may be useful. It is possible to see the Northern lights in the UK, although generally the further North you live the more chance you have of seeing them. The website gives an estimated short term forecast and has map which indicates how far South the aurora is likely to be seen. I have seen the lights when camping in Kielder, Northumberland, but they have been spotted in the South of England to.