How do you find you out the IP address of your computer?
It depends. If you connect to the Net through a router in your house then ipconfig will return the IP associated with your NIC (network card). Usually that will be a number such as 192.168.x.x and is not routable. In other words, that is a private number used by the router to distinguish the different computers in your house that attach to it.
If you wish to find the outbound IP, the one used when going to Google for example, you will need to either use your routers Admin interface or go with the suggestion of using a web-based IP detector.
However, if you are not using a router but are connected directly, then ipconfig will function just fine.
Just thought i'd offer some clarification on the topic.