Linux users,
There was a post over in 'O.S. Talk|PPSoft&Techn.|All Free& Open Src S/W' that announced a panorama-stitching app called XPano:
dprevived.com/t/xpano-new-easy-and-effective-panorama-stitcher/880/
FYI -- The 'Installation' section of the readme on the GitHub link...
...mentions a Launchpad PPA link, which is what I used to install XPano on my Linux Mint.
ssepan1