I just downloaded this myself. WOW! So stinkin' easy! Yes, there are limited choices, but wait until you see them!
I just did this in less than 5 minutes, AND emailed it to family and friends.
Check back tomorrow for the beautiful Birthday cards I received too - I have some VERY talented friends!
The app is only available for the iPhone right now. Enjoy! (And don't forget to leave them some feedback too!)