DP IP’s IP Geolocation Database provides IPv4 and IPv6 address spaces that include more than 2 million unique locations in 215,000+ cities worldwide.
eXTReMe IP Lookup IP Location identifies the specific geolocation information for specific IP addresses in JSON, CSV, and JSONP formats
IP Geolocation AP updates database as soon as they have new information about an IP block and free service is given for non commercial use but a pro service is required for business enterprise.
IP2Location Web Services tracks down geolocation information on both IPv4 and IPv6 addresses, with the option to deliver information via API
IP2Location IP2Proxy Web Service detects anonymous proxy IP addresses using a proprietary algorithm; that pdates every 24 hours