1) Open Google Sketchup (Free): Build a 3D model of a cube and export it as a .kmz file (Google Earth format)
2) Open Photoshop CS5: Open the .kmz file and save as a .psd now.
3) Open After Effects CS5: Select File > Import choose your .psd file. On the dialog screen do Import as Composition and make sure the Live Photoshop 3D option is checked. At this point you have a 3D object in After Effects. If you don’t see the object well it may be that you need to add lights to see it or set your preview channel to Alpha.
4) Make a new square animation composition—I set mine to 200 x 200 pixels. Feel free to animate whatever you want. I did a 6 second animation of a red square growing from the top-left corner and disappearing into the bottom-right one. Alternately you could just do a static colored layer for the sake of simplicity and worry about animating later.
5) Drop this animation you just made into the previous 3D composition as a new layer. Set this layer as 3D layer. Duplicate this layer two more times: your composition should now have 4 layers (3 animations and 1 cube).
6) Switch 3D view to Front and move, rotate or scale one of the animations onto this face, until it meets the edges cube—this process is similar to applying wallpaper to a wall. Repeat this step for the Right and Top sides of the cube and align those two other animations as well (see example screenshot below).