Flex developers can use the ArcWeb Explorer Flex API with Flex Builder 2.01.
While it is possible to connect to ArcWeb Services using Adobe Flash Professional since it supports Web services, the development environment is not officially supported by ESRI.
ArcWeb Explorer is a Flex-based solution demonstrating the types of rich media applications that can be developed using ArcWeb Services. ArcWeb Explorer 1.0 requires Adobe Flash Player 8 or higher. ArcWeb Explorer 4.0 (Lab) requires Adobe Flash Player 9,0,28 or higher.