OS X:
Mac App Store ($0.99)
http://itunes.apple.com/app/elf-ludo/id526690144
iOS:
Apple App Store ($0.99, universal binary)
http://itunes.apple.com/app/elf-ludo-ad-free/id522113826
Apple App Store (free, ad-supported, universal binary)
http://itunes.apple.com/app/elf-ludo/id522102944
Android:
Google Play (free, ad-supported)
https://play.google.com/store/apps/details?id=com.CasualGameStore.ElfLudo
Amazon App Store ($0.99)
http://www.amazon.com/gp/mas/dl/android?asin=B007ZTBDKU
Amazon App Store (free, ad-supported)
http://www.amazon.com/gp/mas/dl/android?asin=B0082CQRPK
SlideMe Store (free, ad-supported)
http://slideme.org/application/elf-ludo