Microsoft's Live Labs have released a new free photo service called photosynth. It is a photo splicing service with a difference, its uses lots of images with lots of overlap to create a convincing 3D view that you can zoom in and out "smoothly" around pan around the scene. Such facilities are not new to the web many real estate site now use walkthroughs, but this is pretty impressive and you can create your own, without much effort. there are two technologies involved the first is the ability to reconstruct the scene or object from a bunch of flat photographs, and the second independent technology, called seadragon, that allows seamless scrolling through 100 of MB over the Internet.
There are two parts to creating your own synths. You must first register at the service, (for which you need a windows live ID) then download a small uploaded application, that not only help you prepare the images and upload them but monitors the splicing process.
There are a few crucial limitations. All syths become public (ie can be viewed by anyone via the internet) but you do have the option of setting the licensing (full copyright or a creative commons) during the upload process. Results can only be viewed on PCs running XP or Vista, which must run the direct-X photosynth add-in for Internet explorer. The 20GB of space seems generous, but you will use this up fast.
One downside is the bandwidth required, I have downloaded it, set it up and uploaded my first project using free wifi at an airline lounge that dropped out a few times so I had to be very very patient!