I also searched this topic high and low on the internet, but found no definitive answer anywhere. So I started pulling stuff off until I found them so that I could change them.
I don't have any pics, but I will describe how to get to the spark plugs on the Pentastar 3.6L V6 motor (and this is specific to the 2011+ Grand Caravan/T&C, but could be similar for other vehicles with this motor).
First, pull off the cover on top of the motor, the plastic one that says "3.6Lvvt" on top. It's just a snap on cover, so it pulls right off. Next, release the three clips that hold the air filter box together (this would be a good time to check the air filter and replace if necessary). Then loosen the far right clamp screw on the air tube that runs from the air filter box to the resonator, and disconnect the air flow sensor. Remove the air filter cover/air tube/valve cover feed hose (the feed hose just slides on and off, just pull it off the valve cover).
Once all that is out of the way, remove the resonator. There are no screws, it just slides out from behind the intake manifold and from the throttle body. At this point you can get to the plugs on the back side of the motor (do these three first before moving on to the 3 on the front). If you look at the pic that kuyabribri linked to above, you can see the three coil packs. Just disconnect the electrical connection, use a 10mm socket to remove the screws, and pull the coil pack straight out. Use caution when removing or installing the spark plugs as the tube walls are thin and can be damaged easily.
Once the rear plugs are done, it's time to move on to the front. You will need loosen all the upper screws on the plastic intake manifold. It's the black plastic piece that was directly under the cover you pulled off in step 1. There are a total of 7 or 8 bolts to loosen from the top, and two nuts to remove from the front (under the radiator hose), before it can be moved. You will not be removing the manifold completely, so no need to disconnect all the wires. The top bolts also do not come out completely, so just loosen them enough so that the manifold can be moved. Once all the bolts/nuts have been loosened/removed, move the manifold towards the rear of the bay. Underneath will be a foam pad that just lifts out, and you then have access to the front 3 plugs. Remove and replace.
Reassemble the parts in reverse order.
If you want to use OEM plugs, they are Champion Iridium, part number CHA 9407. I hope this helps the next person who needs to change the plugs in their vehicle.