In reply to keith-ratcliffe:
Picturenaut is fairly good and easy to use. It has a couple of limitations, but the speed and ease of use make it a good first choice.
http://www.hdrlabs.com/picturenaut/
Another one you might want to try is Luminance. The UI is horrible, but it is fairly capable once you get used to it.
http://qtpfsgui.sourceforge.net/
Neither are particularly good at dealing with ghosting, although they do both have some anti ghost features. It's often not a big deal with landscapes though.