Geo-Names provides free geo-data such as geographical names and postal codes. The database contains over 6 million entries for geographical names and the whereof 2.2 million cities and villages worldwide. The service can be accessed through an webservice API or you can download and use their data to host on your own database server.

The GeoRSS Google Maps API Extention is a simple way to  create  a Google Map using the GeoRSS extension to the RSS standard.  The API extension is simply a small JavaScript library and is very easy to implement.