advanced rendering for AutoCAD
If you have access to a mid level computer, Autocad, and an internet connection you have found the best tutor you could find,....and it's free.
Just dive in using the trial version and asking a lot of questions right here. If you are an old AR3 user you should be able to jump right in and pick things up quickly. There are a lot of new bells and whistles but you can start with the basic stuff. There is a good vidio for beginners that may be beneficial. A link is on the home page I'm sure.