Here is a PDF slideshow giving a nice overview of Libretro, RetroArch and the road ahead for the project –
http://www.libretro.com/wp-content/uploads/2014/03/RetroArch-Libretro-Technical-Brochure.pdf
Tomorrow updated versions of RetroArch for iOS, Android and Wii will follow- some hotfixes here and there (FBA core missing in Android, graphics glitches with Glide64 in Mupen64 iOS, resolution setting not saving in RetroArch GX, etc).