Google Sky
Great overview of online resources for the amateur astronomers @ CNET. Don writes –

This week, astronomers will be up in the early morning hours to see Perseids, a meteor shower that has historically proven to put on quite a show. This happens every August when Earth passes through debris from the Swift-Tuttle comet. If you’re an amateur astronomer or someone looking to get started with the hobby, you might be surprised to know that there are online tools to help you tonight, when you want to see Perseids, and every other night you go in the back yard and set up your telescope.