ok, here it is...
You won't believe how hard it is to take a picture in a dark garage. :)
But this is under the driver side. To the left you see my fog light. In the upper right is the end of the driver side frame rail. This is a 2004 model, so cosmetics may be slightly different, but essentially it should be in the same place. You see one bolt/nut plain as day.
The easy way to find the bolts is to follow the frame rails to the bumper. There will be one bolt on either side of each frame rail. 4 total, 2 per frame on either side of the frame rail.
So lay on your back, with your head and sholders under the bumper. You do not want to take the nut off the bolt, because then your valence would only be attached to your truck by the fog light wiring. Just loosen them just enough so you can move the bumper.
The way I did it was to loosen all bolts (watch out as the bumper will fall a few inches if you aren't holding it). Then have a friend hold the bumper up for ya. Then tighten one bolt on one side. Then have the friend pull up on the other side. Repeat a few times, and inspect the results for evenness before you fully tighten down all bolts.