Beginning Java and Flex : IDE specific?

Is any of your explanation IDE specific in the book? Last I heard is there was not much IDE support for Flex except FlexBuilder

I use the Eclipse Flex Builder plugin. You can use also FDT ( I was using it years ago ) but I suggest to go for the Flex Builder.
You could use also any editor and compile using the Flex command line compiler.

In my book I dedicate a chapter to the IDE configuration in order to start developing Flex-BlazeDS-Spring-Hibernate applications.

Wow a chapter for IDE config

exactly what I am looking for.

You refer to Eclipse Flex Builder plugin but I think that is a commercial one?

yes go for the commercial one.

Download the trial of the Flex builder 3 eclipse plugin. If you don't find it I can help you.