This page at GeekTechnique discusses how most digital cameras are easily turned into infrared cameras by removing the IR blocking filter in front of the CCD, and replacing it with a filter that blocks visible light but passes IR. As luck would have it, exposed film negatives work very well as such a filter.
So I attempted this on my Kodak EasyShare CX6200, my first camera, which somehow still works after 6 years of abuse. It was surprisingly easy, minus the part where I had to manually resolder the coil which controls the shutter on the lens because it was attached by single hair-thin strands of uninsulated wire. But I digress…
I think it’s working well. It very clearly passes IR light because the IR pens for the Wii whiteboard showed up quite brightly; it blocks light from LCD monitors and passes sunlight, but red LEDs seem to show up a bit. Trying it on another camera with more manual controls, and perhaps with a sharper filter, might prove interesting.