How is this done? Trial and error, mostly! I acquired an infrared filter (cutoff 760 nanometers if you gotta know) and plowed ahead.
Some background: the big SLR camera makers like Nikon and Canon have deliberately filtered most infrared light from ever hitting the sensor. Can't blame them for wanting to improve their capture of the visible spectrum. So we have two options. First, for several hundred US dollars the camera can be modified to let IF light through, but the price is turning the camera into an infrared-only camera. Since I don't have an extra thousand dollars to do this, I went for the unmodified option.
Shooting infrared with an unmodified digital SLR requires long exposures, from half a minute to three or four minutes, in my case. I have been finally forced to bring a good tripod along! You can see the length of the exposures in the movement of the clouds, for instance, and in the fact that I chose cacti, juniper and the more rigid plants as subjects. A little breeze will mean a blur somewhere.
This is not a big gallery, because I found that deliberately trying to go out and get IR images was a disaster. Now I just carry the extra equipment all the time, and I'll slowly but surely add many new images here.