WordPress and lots of other applications allow you to see where your visitors are coming from but what if you wanted a quick and simple way to check out an ip address from say a log file or other source.
IPLocation offer such a service for occasional use and will allow up 20 ip lookups per day from an address. http://www.ip2location.com/ is where you will find them but you can use their service like so
http://www.ip2location.com/1.2.3.4 where 1.2.3.4 is the ip address you have an interest in
and you will be rewarded with a screen like this
which gives you some simple info that you may use to further investigate your visitors.