I'm unsure if this will be helpful to anyone or not, but I figured I'd write out everything from the time I first received this infrared converted camera (Rebel XTi) to when I get the hang of it.
After unboxing it, inserting a memory card, and grabbing a lens for it, I turned it on. I immediately got an "Error 99". I removed the battery as it suggested, but it didn't help. I googled the error, tried cleaning the contacts on the lens connection and the battery connection, but continued to get the error. One person advised removing the battery for a couple minutes. I tried that and it turned on just as I was writing an email to the place I rented it from.
Next I took a sample photo out of a window to check the exposure. Converted cameras often need a little extra light, so you have to set the exposure up a stop or so. I took several shots while keeping an eye on the histogram and found that at "0" the histogram was right in the middle. Since there should have been some highlights, I increased it to + 2/3. That was better, but I tried +1 to be sure. That looked good too. + 1 1/3 was too light. So, now I know to increase the exposure by 2/3 to 1 stop.
Next I tried to connect the camera to my computer via USB to download the photos and determine more precisely what exposure was the best. My Windows 2000 machine could not find drivers for it, but my XP computer was able to recognize it.
This reminded me that I needed to see what kind of images the camera was set to record. I usually shoot in RAW and definitely wanted to shoot RAW for my infrared photos. It was taking jpg's, so I made that change and then walked through the Custom Functions to set the autofocus to work via the "*" button and set the directional buttons so they chose the AF point to use. Ah... it feels like my camera now :-).
Now to go out and take some more "real" test shots to get used to it before going on my trip!