I know its been asked/answered before, but everything I look at is from back in July, or otherwise out of date.
Should I bother making my app compatible with iOS 3.x (probably 3.1.2 and up)? Means extra testing some coding changes, etc, etc.
Or are enough users on iOS 4.x that I don't need to worry about it.
If there are any sites that keep up to date (daily, weekly, even monthly) stats, please post.
This answer is 6 years old.
You can confidently ignore 3.x now.
DO NOT BOTHER.
You will find no difference in sales. It's a 4 world as of xmas 2010.