Matt at Raspberry Pi Spy experimented with his Pi NoIR camera module using a Modified Berry Clip and 48 LED IR Illuminator.
Modified Berry Clip:
To start with I decided to try some standard IR LEDs and to simplify the wiring I used a BerryClip PCB to mount six of them. The LEDs were 5mm Kingbright LEDs with an emitted wavelength of 940nM. The BerryClip board (~£6) connects the LEDs (~£2.50) to GPIO pins via 330ohm resistors. This limited the current to each LED to approximately 5mA, way below their 50mA rating. I turned them all on using a simple Python script based on one of the standard BerryClip examples.
48 LED IR Ilumminator:
Next up was the 48 LED CCTV illuminator I ordered on eBay (~£6). It needed 12V but produced much more light. It easily illuminated my office and if pointed directly at the Pi NoIR resulted in a completely white photo! I could position it almost anywhere in the room and the reflected light still gave good images…As you can see from the test shots the lighting you may need for your project will depend on the results you are after. If you are looking to light up a bird box then you almost certainly want to consider using a handful of IR LEDs