DoubleTake is a stitching application for Mac OS X.
It is mainly intended as a non technical way to create larger photos, but it also offers to save as partial or full 360 degree cylindrical QuickTIme VR panoramas.
When you drop images into DoubleTake it will stitch them automatically, but from then on it will allow you to rearrange and tweak with geometric and color correction tools.
Color controls: exposure correction, brightness, gamma and saturation.
Geometric controls: rearrangement, rotation and perspective distortion.