Garden Gnome Software offers the following panoramic image converters:

Pano2VR 2.0 for Windows/Mac/Linux Current Version: 2.0.2, 2008-06-18

Pano2QTVR 1.6 for Windows only Current Version: 1.6.6, 2007-07-30

What is the difference between those products?

In short: Pano2QTVR is the older product, runs only on Windows and depends on Apple's QuickTime. Pano2VR has been completely rewritten, runs on Windows, Mac, Linux, and it doesn't depend on QuickTime (hence the changed name). Pano2VR is not capable of creating object movies.

You can find a detailed comparison on the features page.