Windows software

stitching software

Panorama Tools is a high quality and free panorama stitching software package.

Hugin(free), PTAssembler(shareware) and PTGui(shareware) provide easy to use graphical user interfaces for Panorama Tools

Anything else?

photoshop plug-ins

There are some in the original distribution by Helmut Dersch

viewers

can somebody please link to Fulvio's viewer and other tools?

PTLens

Thomas, how do we fit your wonderful tools in this space? they are not directly used to create panoramas but they are sure part of the family!