On the Spindrop.us blog, there's an interesting post with details on combining the popular PHP framework, symfony, and the Yahoo! Maps system to create maps from a GeoRSS feed.
While building out the reviewsby.us map, I decided to use the Yahoo! Maps API versus the Google Maps API because I wanted to gain some familiarity with another API.
It was worth trying Yahoo!'s API. First of all, reviewsby.us has addresses for restaurants and Yahoo! provides a simple Geocoding REST service. This made it easy for me to convert street addresses to latitude and longitude pairs (even though this wasn't required as we'll soon see). The real selling point of Yahoo! was the GeoRSS functionality. I can extend an RSS feed (which symfony generates quite easily) to add latitude or longitude points (or even the street address), direct my Yahoo! map to the feed and voila, all the locations in that feed are now on the map, and when I click on them, the RSS item is displayed. That cut down on a lot of development time.
He gives an example of a GeoRSS file, including a little bit on changing a normal RSS feed into a GeoRSS one. He then creates a model in symfony to contain the GeoRSS data and a few helpful classes to make parsing out the GeoRSS data quick and easy. He also briefly mentions the creation of a GeoRSS feed with symfony, basically changing an option on creation and using a different (provided) class to format things correctly.