Great info thanks - really useful. On Ubuntu (Jaunty), I found that I just needed to install qtpfsgui (it was in the repos) and this covered the hdr and tonemap creation, I guess the project has moved on since this article was written.
To all the 'hdr looks fake' comments, I strongly disagree. It is easy to produce horrid looking HDR images and its abuse gives it a bad name - just like early (and even modern) use of green screens in movies was often horribly done.
Here's an example photo I edited using qtpfsgui and then gedit for further tweaking. I don't think its a stunning photo but I do think it shows a subtle use of hdr: