IAH - inside the security area, near gate C43

ATL - inside the security area, near gate T9

LAX - inside Ralph's, on Sepulveda Blvd, 1/2 a block from the In n Out. If you know how to get to the In n Out (see the In n Out thread) you can get to the Redbox. Dinner and a movie.

PDX - there is one outside the McDonald's on Airport Way, the road leading out of the airport. Not quite walking distance from the terminal, but located adjacent to the Hilton Garden Inn and its shuttle van, if you get my hint