Joystiq spotted the product page for Monster Hunter Portable 3rd, which will be hitting Japanese PSPs sometime in 2010. It will be the highest selling game in Japan for a while after launching.

New features should include new monsters, areas, improved co-op play, and improvements to the "Felyne Comrade" system. This title will most likely see a release outside of Japan following a localization period, but time will tell if its popularity will grow after the release of Monster Hunter Tri, which I previewed at GDC 2010.