Another issue I ran in to:
When I try to change settings through Settings->Google Maps, I get a
You do not have sufficient permissions to access this page.message while I'm logged in as admin.
Changed I made *are* however saved correctly.
I've read somewhere that WP3 changed how admin priviledges is checked, so may be you could have a look at that.
Additionally, the line underneath the map now always says View larger map. IMHO this should be a language parameter, but as it's the only public one, I'd suggest making it a setting and allowing admins to change the text.