I received an email from a member in long standing this week about a Photo Cube action I'd created years ago. I have updated the action for current versions of Photoshop, as the other action was very out of date.
With this action simply open a photo and press play. The action will guide you through makign a selection in the photo, which then becomes the sides and top of the cube.
1 Action in this set
Simply load the Action set, open the photo, and play the action. Photoshop does the rest