Linux Journal: Geolocation by IP Address

“The Internet has become a collection of resources meant to
appeal to a large general audience. Although this multitude of
information has been a great boon, it also has diluted the
importance of geographically localized information. Offering the
ability for Internet users to garner information based on
geographic location can decrease search times and increase
visibility of local establishments. Similarly, user communities and
chat-rooms can be enhanced through knowing the locations (and
therefore, local times, weather conditions and news events) of
their members as they roam the globe. It is possible to provide
user services in applications and Web sites without the need for
users to carry GPS receivers or even to know where they themselves