Java FX Composer screenshots as well as first tutorials are available. Java FX Composer will (at December, 15th) be an extension of NetBeans 6.8 FX capabilities. It is similar to the already available GUI designer for Swing applications.
NetBeans 6.8 comes already with improved Java FX script editor, and especially: “...improved semantic and syntactic highlighting, source navigation, faster code completion, code folding, javadoc pop-ups, refactoring, and error detection and hints, such as fixing import statements and packages. Now you can Go to Types, Find Usages, and navigate through code with hypertext links...”
With Java FX 1.3 and so the availability of tables, trees etc, Java FX will become a viable alternative to current Swing / SWT / JFace applications.