bagold,
The area for viewing at DFW is called Founder's Plaza and is in the SE corner of the airport. You get to the area off of Airfield South Drive. You would take a left at 30th Street and the park will be on your right. It was built in the mid-90s and does have ATC on speakers if you go up to the monument. I haven't made my way there in about a year. It's really only worth going to when there's a North wind which is when planes will be landing from the South. To get further info on the park, go to this website and click on the Founder's Plaza link on the right side of the site. Enjoy.
http://www.dfwairport.com/guides/visitors/