Who has used this outlet located on the dash and for what ? Has anyone pluged there laptop into it, I was told by the dealer that you can but it does not support a three prong plug.

I used it to power my electric knife for cleaning crappie but have not used it since. You can use an adapter for the 3 prong plug to change it to 2 prong. Some laptops do have 2-prong plugs.

ive used it for my laptop and phone charger

As far as a three prong plug I was told that you can not reduce it to a two plug because of the voltage ?

voltage is the same, the 3rd prong is only a ground incase whatever you have plugged in has a short.

use it to charge my cell phone on the way to work each day

I use it to charge my power tools before I get to the job.

Laptop and phone charger

Bingo. prong 3 is your ground. You can use an adapter if you had to.
Not in my truck, but we have one in our Town and Country and the kids use it to charge thier Nintendo DS all the time!!!

I have an extension cord I plug in. I've had 2 laptops running on it with no problems. Both had 2 prong plugs, but I keep a 3 to 2 prong adapter in the truck just in case I need it.