I've looked at a lot of panorama software. The best free panorama software (actually, the best software I've used) is PanoTools, which you can find:
http://www.path.unimelb.edu.au/~dersch/
It handles panoramas of all types, including the kind you're trying to stitch together with that photograph, and has the ability to automatically adjust colors/lighting to make the panorama more seamless.
Also recommended are both PTAssembler and PTGui:
http://www.tawbaware.com/ptasmblr.htm http://www.ptgui.com/
... as front ends for PanoTools. You can try both of them out via 30 day trialware.
Finally, one neat way of displaying panoramas on the web is using Zoomify's free Flash viewer:
http://www.zoomify.com/ez/
There are some good examples on their site. Here is one panorama from Macau that I did on my trip to China:
http://www.brool.com/china/panorama/...html?image=p10
Good luck.
tim