Unfortunately, HDRShop is no longer available, if you can manage to find it from a 3rd party site, grab it.  I recommend Picturenaut 3, it's a lightweight HDRShop app with some great features.  In addition, pick up Bany's Toolkit plugins, which contain the necessary filter for Diffuse Convolution.  The website you want to go to is HDRLabs.com and both are available for free.  I will continue demonstrations later, I am rushed to eat and get the grandchild to Karate.