Stardoll has created an app for the iPad called My Dream Cakes. You can decorate either a wedding cake or a birthday cake. The app isn't free, it costs $0.99. If you don't want to buy this app or you don't have an iPad, just click the links below to play it on stardoll.
Click here for the Birthday Cake
Click here for the Wedding Cake.
Click here to get the app.