There should be a junction box near the driver's side battery where the 2 batteries and alternator all come together. That is where GM recommends you jump from. There will be a metal tab labeled "GND" as well, and that is where you put the negative cable. If done right, you won't connect to either battery.
At least that is how my 03 is, I presume the 06 is the same or similar.
You shouldn't have any problems jumping another car. I recommend connecting the last clamp on the DMAX, because there might be a spark with the last connection. If the spark is next to a dead battery (which has been off-gassing), it might cause an explosion. If you connect the last clamp to the big "GND" tab on the DMAX, it isn't near any battery, and you're good to go!
Edit: ensure the clamps don't bump/touch your engine or transmission computer housing, as that can fry the computer. That is another reason to use the junction block.
This is the best photo I could find. (Sorry if it is huge.) That red box opens (there is a tab), and inside is where the positive clamp goes. At the top of the picture is the silver tab where the ground goes.