There's a nice new JavaFX plugin available for Netbeans 6.8 - the JavaFX Composer. It allows developers to drag and drop JavaFX containers, JavaFX controls, and project resources to create an application GUI. It also makes connecting to data sources easier.
It's a beta version, but don't let that stop you having a go at creating GUI layouts for your JavaFX applications. It's definitely worth a look. To help you get started there are a few tutorials on the JavaFX Composer wiki.