Well, this is a case where buying might get you there quicker, but there is some satisfaction in doing it yourself. In any case, bgmicro.com sells many different fully assembled IR illuminators.
To help you with the circuit, post the requirements of your IR led. Specifically, you need the forward current and voltage. At that point we'll help you with the power supply and current limiting resistor (which you may or may not need).
dare i tempt fate? What are you _really_ doing with this camera .... my intuition tells me that there is something not quite right about this.