If you use the info windows in the iOS maps, they’re sleek and small and aesthetically pleasing.
The google maps info windows, on the other hand, are huge white blocks with obnoxious shadows. Is there any way to style them– to give them an entirely different appearance?
I think you’re talking about InfoWindows, not info boxes (the distinction is important).
This is a Google Maps Version 3 InfoWindow:
There is an external utility library called InfoBox which allows things like these:
so it is possible to show different styles of information callout, and it’s almost certainly possible to do something like iOS does (image from Macworld):