Rasmus Lerdorf has posted this cool little apps over on his "Toys" page today - a method to create your own geocaching utility, complete with mapping.

Web 2.0 and the programmable web that I and others have been talking about for a while has mostly been vapourware so far. There are a few generic components that are useful, but it is somewhat limited what you can do with them. And yes, you may consider this a somewhat biased view, but I think Yahoo!'s new geocoding platform is a huge step in the right direction.

There is of course the fancy new maps.yahoo.com/beta site which is fun, but as far as I am concerned the killer app here is the geocoding platform that drives this. And it is completely accessible for anyone to use. It's also a sane API that anybody can figure out in minutes. Here are a few tips for using this API from PHP 5.

All of the code you could ever need is here, including how to show a map - via Yahoo - and an example of how it can be put to practical use (a realtime map of the earthquakes on the west coast for the past 7 days).