http://worldphotographic.org/. I will have to say, it was money well spent. Not only are these two guys talented photographers, but they are funny and are really great instructors. Before the workshop you have the opportunity to download a manual, which they refer to during the workshop. I have a much better understanding of ISO, White Balance, Shutter Speed, and understanding exposure. Right after workshop, I participated in a two hour photo walk with Randy Kerr. Although I am not really a portrait photographer, he really helped us to understand light and how to use it to take the best picture of any subject. Randy is very passionate about light and we all walked away with such inspiration. These are samples straight out of the camera. They are not perfect and I can see all my mistakes, but photography is a learning experience and I know my pictures can and will improve.
If you ever get the chance to take a workshop with Doug and Randy, I highly recommend it. Their workshop schedule can be found on their website.