In fact, most digital cameras CCD's have sensitivity to IR by default. (except for some of the canons, those b**tards filter out the IR) so you can drop a R72 filter in front of most digital cameras and get some amazing shots like this...
Jim Chen is an engineer and photographer in San Diego who discovered the exact same thing. That CCD "film" in your digital camera is quite sensitive to infrared light. In order to get natural colors, your camera manufactuer covers the CCD with a very thin IR filter. A clever and skilled person can (very carefully!) remove the manufacturer's filter, and replace it with his own (precision cut!) R72 filter.
The result is a digital camera which takes infrared pictures with the same ease and speed as is once did in the visible spectrum. Without Jim's conversion, taking an IR picture with a digital camera meant a tripod, a lot of patience, and a very long exposure.
I sent him my D70 a while back, after I upgraded to the D200. A couple weeks later, I became one of the only digital IR photographers in Colorado. And that wild puppy pic? All I used was regular old sunlight and a public chainlink fence for a backdrop.