Converting an iPhone app to a Universal app?

Question

I have an iPhone app with FirstViewController and SecondViewController with respective views FirstV

Answer 1

if you are using Xcode4 you can use "transition to universal target" and it will do everything needed

http://xcodebook.com/2011/05/making-an-ios-target-universal/

if you dont have it then I recommend to keep controllers out of your xib. xib files will be only containing views for iphone and ipad but the controllers "can" be same. and you can control your logic from the rootviewcontroller, just an idea..it all depends on your project.