If you haven’t seen the linked video yet, you should really do so. On this years SIGRAPH Ariel Shamir and Shai Avidan presented a new algorithm titled “Seam Carving”. It allows to stretch or squeeze an image without distorting the overall looks. It’s as if you shrink something, but only in one dimension. A corresponding YouTube-Video can be found here.
Now Adobe announced, that they employed one of the developers of the algorithm. So expect to have this feature in Photoshop rather sooner than later.