Here are some links to Punnett Square Simulations
http://www.glencoe.com/sites/common_assets/science/virtual_labs/E09/E09.html
http://www.zerobio.com/drag_gr11/mono.htm
http://glencoe.mheducation.com/sites/dl/free/0078757150/383934/BL_05.html
http://sciencereviewgames.com/srg/games/hs.php?id=136
If you are really good, try taking this quiz.
http://glencoe.mheducation.com/sites/0078778066/student_view0/chapter5/math_practice.html