We're pleased to announce that we've joined forces with the other Arduino-based powerhouse in the aerial robotics world, the AeroQuad quadcopter team, to extend the ArduPilot platform to whirlybirds of all kinds. The project will use the ArduPilotMega and IMU shield hardware along with a low-cost custom platform that will be available commercially to provide a full quad UAV with both stabilization and GPS waypoint navigation. It builds on the awesome work of Jose Julio in ArduPilot quad development, with the excellent full-systems integration of the AeroQuad team. We expect that first code and hardware will be available this summer.
Arducopter dev team member kinderkram's RCGroups blog.