Rasmus Lerdorf has a post filled with Yahoo! maps API examples:
“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.“