Capetonian,
Being the important keyword.
As MacBoero implies, there are a number of geolocation databases out there that attempt to map IP addresses to a location. They vary widely in their accuracy and update frequency.
Accurate geolocation of an IP address is not necessarily entirely big bad big-brother. For example one good location for accurate geolocation is for CDNs (content delivery networks) such as Akamai and Youtube who would like to be able to point you to the nearest datacentre so that you have a pleasurable viewing experience. However, of course, this doesn't need cm level accuracy, the sort of thing that might be useful for is if your using your device for navigation and are in an urban canyon.