Nathan Mrvichin, a student at the University of Texas Austin, created an online program to review the Yookoso vocabulary. It has all of Yookoso! Introduction vocab (vol 1) for a review, and he is adding Yookoso! Continuing vocab (vol 2) as we go along in class. It is a very good self assessment tool.
Editor’s Note: the explanations and format of the site need some help, but stick with the four links at the top and you will be o.k.