Photosynth (by Microsoft) is worth downloading from the App Store!
What is Photosynth? It is a free application for PC users and mobile devices that can capture a 3D space. Think Panorama except it can cover the full 360° including floor and ceiling.
Examples from photosynth.net
It could not be more intuitive, the hardest part is rotating the device and keeping the lighting consistent.
Once everything is captured Photosynth uploads to your free account or stores on your phone. PC users can also stitch directly on their home PC’s.