UK PostCodes:
http://www.uk-postcodes.com/api
PostCode Details: http://uk-postcodes.com/postcode/KT47QX.xml
Reverse Geocoding
Google Reverse Geocoding
Find Latitude,Longitude pairs based on a postal address
Free Geolocation Finder:
http://freegeoip.net/?q=62.232.92.61
HTML5 Geolocation
http://www.w3schools.com/html/tryit.asp?filename=tryhtml5_geolocation
IPInfoDB
http://www.codeproject.com/Articles/185508/IP-Address-to-Geolocation