Helmut Dersch's excellent (and free!), Panorama Tools software is the
best I've seen for correcting lens distortion. Even fisheye lens output can
be corrected to true rectilinear.
For critical work, individual lens distortion parameters can be calculated
by photographing a known true grid and analysing the output (film or
digital), with the software.
Quicktime does a lot more than show videos, for instance, using cubic
projection it can show fully immersive 360 degree panoramas.
MEGALITHICS - VR panoramas, images and information on megalithic sites in the British Isles and Eire.