Did you try using google? The first search hit for IPInfoDB gets you to their site. Clicking on the Database tab gets you to the page you are looking for:
ipinfodb.com/ip_database.php
Data accuracy
Over 99.5% on a country level and around 80% on a city level for the US within a 25 mile radius with the complete database. With the small version you get very good accuracy while having 65% less row. Most IP in the 123.123.123.0-255 range are very close to each others.
The data is compiled from the free Maxmind CSV database (Geolite City) and rearranged with many scripts. We use other sources such as Geonames for timezones, FIPS for regions name and IANA for IP assignement. If you wan't better precision on a city level, MaxMind offers great commercial products. In no way our site is related to Maxmind but since we use their free database to build ours, we wanted to thank them by putting a link to their site for those that can afford their commercial products.
Like horsepower, you get what you pay for.
Mike