Not so long ago iPhone development was quite simple, only a few OS versions and even less devices.
Now however, there are 2 major OS versions and 5 different devices to
I am not sure if its a best practice. But I have heard many people using ibetatest for exactly what you are looking for. Lots of enthusiastic beta testers out there. You shouldn't have any issues on 95% of your code running on different versions, and something like ibetatest should catch the remaining 5%.