Quicktime is the original way to se VR Panoramas. It gives you optional quality also on older computers witth minimum Ram and slower speed. QTVR Movies do not need fast Videocards with large Ram
DevalVR
DevalVR is a popular panoramic viewer to show QuickTimeVR files on the Internet. DevalVR is a very small plugin (~250kb).
Adobe Flash Player
SPi-V is hardware accelerated panoramic viewing engine. The engine was build on a solid and extensible multimedia core provided by Adobe Shockwave Player.