Not that I know of. There are settings in PS to deal with the anamorphicness though. So if you're coming back to video, just leave it as is.
If you're not coming back to video, just make a fullsize psd (in PAL that would be 1024 x 576) and drop the frame on that, which will automatically centre it . Then just grab each edge and pull sideways until you hit the canvas edge. Save. Done.