Who doesn't love their cell phone right? (and how did we ever live without them?!)
To make it extra personal, you can make your apps on this iPhone (or similar phone) relate to the birthday person too.
You could make the apps with fondant, if you have the time and love to work with it, or in a rush you could just print the apps on heavy cardstock or something that won't be affected by the icing, and place them on the cake.
Or use M&Ms for colorful "apps!"
You might also enjoy an Ipod cake!
How to make fondant:
Combine gelatin and cold water and then let it stand a few minutes until it thickens.
Place the gelatin and water mixture in the top of double boiler. Heat and stir until dissolved. Add glucose and mix. Add vegetable shortening by stirring it in. Remove from heat just before it is completely melted.
Add glycerin, plus any flavoring and any coloring.
Once lukewarm, pour confectioners sugar into a large bowl and create a well in the middle. Pour the gelatin mixture into the well, and stir with the spoon until no longer sticky. (Use a wooden spoon.) Knead until smooth and no longer sticky.
Store up to a week in an airtight container at room temperature or refrigerate if storing longer. Knead it again when you are ready to use it, to make it soft. If it has been in the refrigerator, bring it back to room temperature before kneading.
Show us your great birthday cake and tell us how you did it!