I wrote Korea has been served the interactive map service made by ActiveX and Java applet by broadband and IE exclusive environment in my A Mashup with Google and Korean Map. Unfortunately Firefox users cannot use map services in Korea.

But, Naver firstly changed its map service to Ajax based without Active X plugins.

In korea, there are several map service providers Congnamul and SundoSoft. Sundosoft is the provider of Naver and Nate. So I expect most of portal will change to operate their map service under cross browsers and platforms.