There are a multitude of programs to handle and process HDR. Today almost all standard photo editing software have some kind of support for it – with varying degrees of freedom and finesse.
Photoshop have had it for quite some time as well has other more or less high end photo editing software. The one I like the best, and that I use almost exclusively, is Photomatix Pro.
Photomatix is done by a small company called HDR soft and they have a very nice and reasonable licensing scheme. First of all, you can download it for free and try it out. This gives you some limitations as well as watermarks all over. Still, you will not by it without knowing its capabilities.
Secondly, once you have bought it – it is yours. You have a personal license key that you can use on all your computers. The only requirement is that you only use the software on one installation at the time. This, I believe, makes sense to a lot of people that have laptops and stationary computers that they use interchangeably. It also covers different architectures. So if you have a stationary PC and a MAC laptop you can have the same license on them!
I have used Photomatix for close to three years and so far all upgrades has been for free – also something to note when you compare to certain other larger companies..
I get nothing from pitching Photomatix! I just wish HDR soft to be successful and for you to find this nice, cheap tool.
All these pictures and more can be found at http://reveman.smugmug.com