Attached Link: http://www.americaswonderlands.com/digital_photo_interpolation.htm

Here's a GREAT Review that compares a whole BUNCH of software methods. The reviewer doesn't select a winner- but there are a lot of sample images to help you understand what they all do. NOTE: This review doesn't include the current NEW versions of Stair Interpolation 2 or Genuine Fractals 4.1-- both of which have substational enhancements as new versions have just been released...