Google Earth - World travel from your desk.

No more expensive vacations! You can now travel the world in one click - for free! With Google Earth, that is. Google Earth (made by, you guessed it, our friend Google) uses satellite photos of the entire earth (mostly, anyway; Google excludes some places because of security reasons) to construct a virtual globe inside your computer.
With your mouse, you can interact with the world by zooming in and out and panning through the image. But that's just the beginning. You can type in an address, directions or coordinates and instantly be taken to the geographic location. Many cities have 3D buildings, and there's a neat new feature called Street View that allows you to take panoramic tours of select cities. You can also see the sunrise and sunset happen in real time, or change the time of day to see the sunlight move across the earth.
There's a neat feature called Sky that lets you explore beyond the earth in outer space, seeing other stars and galaxies. There are so many amazing features in this program that I can't mention them all, but you can get a great tour with videos at http://earth.google.com/tour.html, or if I've already convinced you, go to http://earth.google.com/ to download it. It's free!