Gracenote makes a music popularity world map, where you can check top artists and album charts by geographical location, in most countries (at least definitely all countries that actually have an influence in international music sales, and then some).
All you need is to have the Flash plug-in in your browser, and you can check very interesting statistics. The map uses data from the Gracenote Media Database® and shows the latest album and artist lookups in states, countries and continents around the world.
Definitely worth a check! Specially if you’re a songwriter/business person and even producer.