I might be the last one to discover this, but last week a friend showed me Google Earth and I am hooked now. It seems that Google bought out Keyhole (a dotcom startup company, which spent 4 years stitching together statilite & aerial photography photos) last year. I can see my dad's hot tub in his back yard, my brother's pond, and even the pyramids of Giza! Soo cool! Keep in mind that the photo's are 1-4 years old and are not current, it is amazing, AND scary at the same time!
http://earth.google.com/
Oh, and if you haven't used it yet, and want to, download the free software (10mb) and remember where you save it, because you have to click on it and unzip and install the software from there. You need a decent video card, and PC for it to work well. If you have a kick-ass video card, then you might be able to count the shingles on somebody's house!
Oh, and I was even able to find my favorite mtn bike trails in the photo's, as well as slickrock in Moab! Crazy!