I haven't seen anything in the menu's with regard to geometry correction nor the ability to turn it on or off.
What I have noticed, however, is the frame around the screen is pretty weak imo. I can push and pull around the upper left corner and it corrects the problem. If I pull out on the bottom left and push in on the top left, it corrects itself. Trouble is getting it to stay that way. So to me it looks like an issue with the frame rather than the electronics. I read through some of the 2008 threads and numerous others had the same issue.
Watching normal tv both SD and HD it is a non-issue. It's a little noticeable when the program guide is up from DirecTV, but I have yet to notice it during an actual broadcast.