A WebmasterWorld forum thread named Yahoo Ambassador Test discusses the different levels of ambassador programs available at Yahoo! and how hard the tests are.
After you pay the non refundable $50 in the Ambassador sign up link, you have access to the training. There are 13 modules with about 4-8 items in each module. It does not seem as comprehensive as the AdWords training, but I have learned much new information already that has already helped with the Yahoo Ad accounts that I am managing now.
The discussion then moves into the types of programs available. There seems to be some confusion as to if there is a minimum spend to be part of any of the programs or not.
Forum discussion at WebmasterWorld.