Here is a list of many useful links to web sites where you can find a lot of knowledge and electronic modules for your designs.
UAV DEV BOARD – the most useful website which will guide you in depth in flight stabilization and autopilots.
MatrixPilot – the UAV DEVICE BOARD original firmware.
Main UDB Discussions group – Main UDB discussions group.
UAV Developer Discussions group – Developer’s discussions group.
UAV Heli Developers group – Heli Developer’s discussions group.
DIY Drones – The home for everything about amateur Unmanned Aerial Vehicles (UAVs).
SparkFun Electronics – One of the best electronic shops for UAV components.