Have a look at this one click here. Or if you know of any Canon users they could supply you with "Photostitch" this is available as a free download to Canon users.
On your sample picture are you concerned about the misalignment or the curvature/distortion?
A lot of the cheap/freeware pano software do have problems with the correction of verticals. This is relatively easy to correct in such as Photoshop or Corel Digital Studio 2010. A good cheap way to obtain this software, is to enter a good winter photo in the PCA winter competition:)
I have corrected the vertical and and cloned out the misalignment and also reduced the blue a touch.
I will place the photo on Adobe Photo Express for a couple of days so that you can check it out.