The guys at Codehoop have done a great job! And here is a couple of movies they have put together to help users install the editor and view the OMG BPMN2 examples.
Note: the editor is based on Graphiti, which is only at version 0.7.1, and an early version of the Eclipse BPMN2 meta-model, so this is still a work in progress. So expect to find issues with any of the new technologies. However I would encourage you to download the editor and have a play.
The current editor provides the base level capabilities for creating a BPMN2 compliant model and diagram. However as with any new UI, there are areas where usability improvements would be required. This is work that will happen over the coming months, so feel free to express your views on how the use experience can be improved.
At the moment the issue reporting for the editor is through the jBPM project, using the 'Eclipse' component. However we are working towards moving this editor to Eclipse.org .... so watch this space.