There are many ways in which you can create an awesome Little Big Planet birthday cake or cupcakes.
One idea would be to top your treats with the earth globe sugar decorations pictured here. Each earth globe measures 1 1/4" in diameter and they come with 12 edible toppers per order.
Ebay sellers offer a nice selection of edible cake and cupcake images. These toppers are very simple to apply to your home baked or store bought birthday cake. You can choose from many designs and some of the toppers can be personalized with your child's name and age.
You could also make Little Big Planet paper cupcake toppers. Simply print out LBP images online and print out onto photo paper. You could also purchase stickers on Ebay for your toppers. Then matte onto cardstock and punch out using a circle paper punch. Attach a toothpick or lollipop stick and insert into your frosted cupcakes. If you have never made paper cupcake toppers before, please visit my Cupcake Topper page for complete instructions, photos and supplies.
The last idea I am featuring here is the zipper silicone mold. This zipper mold can be used to create wonderful Little Big Planet inspired designs on your cakes with fondant or sugar paste.