3D Rotating Camera

Hello. I have tried several things, but would like to know the best and fastest way to do this. I was wondering how to make a 3D rotating camera in my engine. It just came up that we want one, so I would like to put it in. Our main view is a set RTS standard view (for demo purposes it is at x45°, y45°, and z45°) We also are going to add a FPS view camera. But the 3rd and final view is the 3D floating camera. What is the best way to go about that? We are doing all of our rendering in DirectX 7.0a to 8.0 (16 bit). Thanks in advance! ======= ~Khaos~ =======