Joomla!: IP2Location Visitor Location & Weather Extension
This extension is using IP2Location database to trace your visitor's actual location with latitude and longitude, city name, state/region, country name and even the current weather status at their place.

http://extensions.joomla.org/extensions/external-contents/widgets-a-documents/9877

Drupal: IP2Location GeoLocation API
This is a IP2Location GeoLocation API to query IP2Location BIN database.

http://drupal.org/project/ip2location

OSCommerce: IP2Location Form Auto Selector v1.0
Auto Selector detects the visitor's physical location automatically. It will fill up user registration forms and shipping forms based on the visitor's origin. Fields supported by this module include Post Code, City, State/Province, Country, and Area Code. This will accelerate the purchasing process and provide a more user-friendly interface for users.

http://addons.oscommerce.com/info/6955

WordPress: IP2Location Tags
Use the [ip2loc][/ip2loc] tags to dislay geolocation information of your visitors. You can use this plugin to block/display customized post content as well.

http://wordpress.org/extend/plugins/ip2location-tags/