From wired to remote control?

Is there any general information I can read on the steps on how to convert something wired to remote control? I want to start simple like a small motor (like you would find in an RC car or something. Simple controls, off and on. With the possibility of speed control.

Check robotics hobby sites.

For motors, you would use H-bridges, or a pair of relays., and a microcontroller to receive and decode remote commands, from a typical IR remote.

Create Simple Remote Control for Ubuntu / Windows