I've added some more advanced FlexUnit cookbook recipes that cover testing visual components and automated TestSuite generation. These can be found at Testing Visual Components with FlexUnit and Automated TestSuite Generation respectively.
I've posted round one of some Flex Cookbook entries that focus on FlexUnit. I welcome any feedback on have about them.
I added a couple more introductory FlexUnit recipes to the Flex Cookbook. They are titled Understanding FlexUnit Output and Run code before and/or after every test. Next up will be some intermediate recipes.