EchoStudio 2.0

EchoStudio 2.0 is an Eclipse 3.1-based rapid application development tool capable of creating web-based applications that work and act like rich clients. Building upon the power of the open-source Echo2 Framework, EchoStudio offers easy-to-use tools that enable developers to design more compelling user interfaces in less time.

Come to more detail: http://www.nextapp.com/platform/echo2/echostudio/