There are two options:
1) EDIT: Since 7u35 (or smth near it) JavaFX was included into base JDK classpath so you can use JavaFX classes right away.
Just set up your projects to use fx libs:
JavaFX 2.0 API is pure Java. So you can create a new Java project and add
sdk-path/rt/lib/jfxrt.jar to libraries to use JavaFX in that project.
For cobundled builds in JDK7 path would be next
2) Use e(fx)clipse plugin: http://www.eclipse.org/efxclipse/index.html