I am proud to announce the launch of my new project GeoJS! GeoJS is a highly available REST/JSON/JSONP IP/Geolocation lookup API. It enables websites and platforms the ability to request information about their IP or a specific IP, be it geo location or just the IP they're requesting from. It has no rate limits (yet!) and is 100% free for use.
Built upon Nginx and openresty's lua-nginx-module it offers sub second response times around the world which you can confirm via our status page. It was built with simplicity in mind but if you find something dire that you feel is missing please don't hesitate to reach out.
P.S. You can see it being used right now next to the tags for this post. Neat, eh?