It isn't too difficult to create a photocube in Photoshop, there are a lot of tutorials online to walk you through that. However, it is time consuming and hard to recreate without going through the same lengthy process.  A much easier way to do it, is to use Photoshop actions to perform the tasks automatically. I like to use a fairly inexpensive product from PanosFX.com. You basically just choose
the type of cube you want, it steps you through loading of photos and then you can still tailor as much as you like. They also have quite a few other products using Photoshop actions that create some fun effects. It makes a perfect cube if you use square
pictures but I also like the effect of using full size landscape shots like the example I did below using a few Seattle pictures I just took.