Understanding 3D Rigid Body Transformation

A good tutorial on 3D rigid body transformation, Euler angles i.e. roll, pitch and yaw, the rotation matrix can be found in the link below.

Just traverse to before and next sections for better understanding :)

http://planning.cs.uiuc.edu/node102.html

http://www.cs.iastate.edu/~cs577/handouts/homogeneous-transform.pdf