(Update – adds video of Photosynth demo)

If you’re snap-happy with your digital camera, Microsoft thinks it has the Web site for you. Microsoft Photosynth is a new, free photo service that stiches together pictures (preferably lots of them) of a place or a thing to create a 360-degree visual experience. You can zoom in and out smoothly, pan left and right, up and over.

Here’s the description of how Photosynth works from the Microsoft press release.

“Photosynth analyzes each photo for similarities to the others, and uses that data to estimate where a photo was taken. It then re-creates the environment and uses that as a canvas on which to display the photos.”

To get started, you’ll need to download a software application. Sorry Mac fans, it’s PC-only for now. David Gedye, a Microsoft group manager who leads the PhotoSynth team, assured me that the Windows-only situation is only temporary.

Once you have the Photosynth application, it’s pretty self-explanatory. Upload the pictures and let the “synth” begin. I found that you have to take LOTS of pictures to create a good synth, which probably explains why Microsoft is providing 20 gigabytes of storage for users.