OpenStreetMap is a global project with an aim of collaboratively
collecting map data, and today Ken Guest has submitted his PHP package for communitcating with the OSM API to the public and the PEAR PEPr review process:
So over the last while, I’ve been working on a PHP package imaginatively named Services_Openstreetmap, for interacting with the openstreetmap API. I initially needed it so I could search for certain POIs and tabulate the results; it’s now also capable of adding data to the openstreetmap database – nodes and other elements can be created, updated and so on. It will even access the details of the user that is being used to modify that data, which is one difference between it and the other single purpose OSM frameworks. --Ken Guest
You can view the submission here, and you should definitely take a look at openstreetmap.org if you haven't already. Good news for PHP developers looking to use this project more heavily in their applications.