Photosynth is, without doubt, one of Microsoft's more impressive mobile apps. The app lets you snap panorama pictures with your iPhone and then upload them to Photosynth.net (and you can even get them featured on Bing Maps). While the mobile app doesn't give you quite as many features as the web app – which allows you to stitch together 3D panoramas by combining images from multiple perspectives – the app has proven to be quite a hit.
According to Microsoft, 6 million iPhone users have downloaded the app so far (though, as usual, it's not clear how many active users there currently are). More importantly, though, the company also today announced that Photosynth is now available worldwide (iTunes link).
Also new in the latest version is a tighter integration with Twitter (via iOS5's built-in Twitter capabilities).
In case you are unfamiliar with Photosynth, here is Microsoft's description of the app's capabilities:
Capture Full-Sphere Panoramas: Look and capture in all directions more easily than what most of us can do with DSLRs and point-and-shoot cameras.
View immediately: With fast On-Device Processing, you can see the final panorama in a few minutes, without requiring an internet connection or data plan. Very handy for those impromptu panoramas and immediate gratification that you captured the perfect shot.
Save locally and on the cloud: Your panoramas saved on your phone can also be saved and viewed online at http://photosynth.net.
Share immediately: Share your panorama immediately via Twitter, Facebook or Bing Maps.
View in browser or app: Zoom, pan, and rotate your panorama in any direction through the Photosynth app or through the mobile browser.