Many folks in the USA are now hooked on Google Map's innovative web based mapping system. What makes Google different from MapQuest or Yahoo! Maps is its java based interface which lets you drag-and-scroll in real time as well as its satellite overlay and new hybrid overlays. Google Maps has recently spawned Google Maps - the Moon.
Google has recently teamed up with Japanese cartography company Zenrin to bring Google Maps to Japan. The interface is provided in both English and Japanese, but most of the map detail label are in Japanese. While you can ask it for detailed addresses like "千代田区永田町1-7-1", you can't do point to point driving directions (yet). If only they had this when I was doing my fieldwork!