Here's a good idea of what I want it to look like (best way I can think of):

http://img.diytrade.com/cdimg/...ghting_LED_light.jpg

I want to have a turntable thing that sits on the floor (like the picture), with with motorized....things.....that support the "light" (as in the picture).

I want to be able to set the speed of both motors described above using a computer, but I have no idea how. Also, I want to be able to have a sensor or something that can detect the angle of the turntable and support things somehow, and be able to receive that as input on a computer.

Instead of a light, like the picture, I want to have some sort of sensor that will emit a "sonar" type thing and give the computer the time that the sonar was fired and the time it was received.

Summary of Questions:
- How do I talk to motors and sensor with a computer?
- What kind of motors/sensors would I use for the robot described?
- How do I power this sort of thing?
- How would I get the necessary parts to build it (design them, order them, etc)?

I have a decent amount of software experience...but when it comes to actual robots I'm completely lost.

Any sort of references or something would be great. Feel free to answer whichever questions you wish.