Ryan at The Channel Project loves his iPhone 3GS — and his Mophie Juice Pack Air rechargeable battery pack — but doesn't love their lack of a photoflash.
So he modded the Juice Pack with an LED from SuperBrightLEDs.com, and a switch and cap from some Home Depot flashlights. Total cost? Under twenty bucks. Improvement in iPhone snapshots? Priceless. (And as a reader pointed out, since the LED stays on as long as you hold the switch down, it doubles as a video light!)