Are there any official certification programs by Apple for iOS App Development?
Apple has hyperlinks to all of the topics they do provide certification for off of this page. At this time it is only Mac OS X IT-related and 'Pro Apps', meaning Apple apps used by creative professionals/iWork.
I am not aware of Apple-sanctioned certifications for software development. From the Apple Certifications page there are only two tracks - IT and Creative. Becoming an Apple Developer gives you access to Apple material such as Tech Talk and WWDC sessions, but there is no official certification path as far as I can tell.
I have read wonderful things about training at the Big Nerd Ranch and at the Pragmatic Studio, but I haven't experienced these courses myself (yet). Both of these places are well regarded in the community and while they do no not offer certifications per se, they still seem like terrific alternatives for training. Hope this helps.
While not available initially, Apple has recently partnered with a widely recognised, 3rd party training provider LearnQuest. LearnQuest claims to be an Apple Authorised Global Training Provider.
The App Development Training Program mentioned on LearnQuest lists the following training paths as of this writing:
All three of them are classroom courses. These courses are targeted towards Software Developers, Software Architects and Technology Consultants.
Note: The hyperlinks mentioned in the answer direct to the courses available in the current country of my residence. You may need to switch to the desired country page on LearnQuest's website.