So, to sum up:
To view panoramas on Photosynth.net:
:: Windows Phone 8 devices, Windows RT devices (like the Surface RT tablet), iPhones, iPod Touches, + iPads can all use the HTML5 panorama viewer in Internet Explorer 10 or Safari.
:: Windows Phone 7 devices, iOS devices, + soon Windows Phone 8 devices can download Photosynth's mobile panorama app to create panoramas on the go as well as viewing panoramas with a better framerate than the HTML5 viewer.
To view photosynths from Photosynth.net:
:: On iOS devices, people can use the unofficial iSynth app to view photosynths. http://bit.ly/isynth
:: On Windows Phone devices + Android devices no one has provided an unofficial photosynth viewer app.
:: The HTML5 viewer cannot yet handle viewing photosynths.
:: The official Photosynth app does not yet view photosynths on either Windows Phone or iOS.
:: Windows PCs + Macs c an use the Silverlight viewer which has more features than the HTML5 viewer + opens synths.