uPano (Unity Panoramic Framework) is a universal multi-platform solution for displaying dynamic and static panoramas, and creating virtual tours.
uPano is very easy to learn and use, and is great for people who do not have programming experience.
Visual Tour Maker lets you create virtual tours in minutes.
In most usage scenarios, you can make interactive panoramas without creating your own scripts.
If you have some very specific purpose, uPano has a powerful and easy-to-use API that will allow you to implement any behavior.