In this first part, he just makes sure that you have what you need installed before really getting started. Brief installation instructions are provided and example code is included to make sure things are up and working correctly (a lookup for whatever IP you're coming from).

It uses the lookupCountryName method to translate the information based on the MaxMind data.

Through Planet PHP I found an article on Pre-populating forms with the timezone. I'd normally add a comment instead, but the comment would almost be larger then the original post, so I am instead writing up an entry myself. The post describes several ways to obtain the user's timezone and use that to pre-fill a form. None of them are working properly though.

In Derick's method combines a bit of Javascript with some PHP to correctly find the timezone.

In this tutorial, we'll take a look at the technique of geotargeting, or serving content to users based on their physical location. The technology is invaluable; with simple techniques, you can target advertising to specific users, collect more accurate usage statistics, serve content in different languages for different regions and provide local information like weather reports to your visitors.

They use the GeoIP services offered by Maxmind to perform the IP to location translation and the PEAR package already created to make the integration as painless as possible.