Is there any way to protect your flash work? To be honest the answer is NO. As you probably know everything that is uploaded on a web server and is accessible from a web browser is downloaded to the users' computers and could be found in the temporary directories. Once someone gets your swf file he could use one of the dozen decompilers to reproduce the .fla and .as files. Anyway, there are still some ways to make stealing difficult.
I'm absolutely sure that you've already met this problem. You know, these nice rounded buttons that are provided by the designer. They are really cool, but sometimes the label of the button is so long that you have to resize/scale the image. ActionScript3 provides simple way to solve this issue.
One of the big advantages of Flex framework is that you can use a lot of ready components. The DataGrid is really helpful. Especially when you want to list big amount of data and provide ability to edit the information directly in the grid. These days I finished a test task which uses DataGrid and decided to share my experience.