Russell Ivanovic dispells the myth of Android screen fragmentation:

Seems like a lot of variation, right? The part that might confuse most non-developers, is we lay everything out at ‘1x’ or ‘1dp’. So on the iPhone you can have a 320×480 pixel iPhone 3G, and a 640×960 iPhone 4, but the interface itself doesn’t change, it’s still 320×480. You don’t have to re-lay out any buttons or do a custom interface for it. All you do is provide higher resolution assets to make things look crisper. The same is true on Android.
Android has come a long way.
If they ever decide to get rid of that awful Helvetica/Arial-mutant-lovechild Roboto, I might actually switch off iOS.
Ha. Who am I kidding, no I won’t.