I recently wrote an iPad app that I would like to make a universal app.
What is the best way to do this? Can I simply create two versions of my XIB files and load the appropriate XIB based upon the device?
This should help you out a lot: http://iphonedevelopment.blogspot.com/2010/04/converting-iphone-apps-to-universal.html
Yes, you can create 2 xib files for every screen (one for iPad, and one for iPhone/iPod).